


Tony Stark and the Heterodyne Legacy

by Jamoche



Category: Girl Genius, The Avengers (2012)
Genre: Crossover, Gen, Girl Genius AU
Language: English
Status: In-Progress
Published: 2013-02-27
Updated: 2017-02-03
Packaged: 2017-12-03 18:58:47
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 10
Words: 23,541
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/701568
Author URL: https://archiveofourown.org/users/Jamoche/pseuds/Jamoche
Summary: <blockquote class="userstuff">
              <p>Loosely inspired by Euphrosynia's Jäger by khilari - What if the Super Soldier serum was the Jägerbräu? </p>
<p>AU for Girl Genius: When Tony Stark's great-grandfather helped fellow student Agatha Clay recover her lost locket, she never made it to the university the day Klaus took over, and the world became a very different place. But Heterodynes can't stay lost forever, not when there are Jägers on the hunt.</p>
            </blockquote>





	1. Chapter 1

**Author's Note:**

  * Inspired by [Euphrosynia's Jäger](https://archiveofourown.org/works/646182) by [khilari](https://archiveofourown.org/users/khilari/pseuds/khilari). 



"I'm here to rescue you."

The speaker smelled like a Jäger, so Maxim knew it was another hallucination. Pity. A rescue would be nice. Still, it was better than the usual one where the Castle had gone up in a massive explosion, taking out the fake Heterodyne, Castle Wolfenbach, and all the Baron's Jägers, just as sharp as the day it had happened. Or the ones after that, where - no. If whichever madboy had captured him _had_ to invent a drug that could keep a Jäger under - more or less - why couldn't it give him pretty girls instead of bad memories?

Or rescues. He wasn't going to argue with that. "Dat'z nize," he said. "Even if hyu izn't a pretty gurl."

"No," the rescuer said, frowning. "I'm Captain Rogers. You've been drugged, which… is probably a good thing, considering." The look Rogers gave him had him wondering what could be wrong. He staggered to his feet and looked himself over. Everything _seemed_ fine - arms, legs, hat - he patted his head to be sure. No hat. 

"Def'nit'ly a bad plan," Maxim muttered, though he couldn't even remember if there'd _been_ a plan. Or much of anything, for that matter. "Mebbe your plan iz better?" he asked Rogers. Who he was beginning to believe was real, even if he _did_ still smell like a Jäger.

"Yes," Rogers said, still looking at him like he was a bomb with a lit fuse. "Rescue a friend of mine. I could use your help, if you're willing."

Maxim shrugged. "Sure. Hy need to find de guy vot took my hat."

~.~

Tony Stark smelled _good_.

"Who's your purple friend?" he asked Rogers.

"Ah…" Rogers said with a _shushing_ motion. "Found him chained up in a cell." He added quietly, but not so low that Maxim couldn't hear him, "One of the failed experiments, apparently."

"Hey," Maxim protested, "Hy iz Jägerkin, not a failed eks-eks- vot hyu said."

"He's not," Tony said, looking at him oddly. "They haven't gotten that far."

"But the way you fought," Rogers said, obviously baffled. "Even drugged, you kept up with _me_. And you're, well-" 

Maxim looked at his arms - "Purple, yez" - everything was good there. Looked at Rogers. Blinked. "Vait, hyu tink I vaz - but hyu iz -"

Tony smirked. "Meet the first - and only - successful product of the Super Soldier serum," he said, with a sweeping gesture that missed out on the full dramatic impact by the clink of chains holding him to the wall. "Often imitated, never duplicated, though our esteemed hosts seem to think I can do what they can't. Given that my father worked on the original."

Maxim shook his head, trying to clear the cobwebs. Rogers smelled like a Jäger, fought like a Jäger, and Tony smelled like - "Ov kourse," Maxim said, slapping himself in the face. "Hy iz schtill on de goot drugz. A Jäger askin' me to rescue a Heterodyne ken't be real." Or maybe a new kind of torture… "Hyu tink dis vill break me?" he shouted at the ceiling. "Hyu tink Hy dun' know how Hy failed? Hyu tink-"

"You're a Jäger?" Tony asked, cutting off a really good and long-overdue rant. "Shouldn't you have a hat?" 

Torture, definitely. "Yez, but-"

"The Heterodyne shock troops?" Rogers asked. "We heard rumors that HYDRA was hunting them during the war."

"Looks like they found one," Tony said, as he walked around Maxim curiously, and stopped - much too close - once they were face to face. He really _did_ smell good. "You really were constructs? I thought that was a myth. But of course, the stories, the serum - it has to be-" Tony's voice started to take on the harmonics of the madness place.

"Tony!" Rogers snapped, with a pointed glance at the ceiling. "Not here." He turned to Maxim. "Whatever you are - whatever you think - we need to get out of here. Now."

"Right," Maxim said, impressed. There weren't many who could stop a Heterodyne when they started getting sparky like that - or would be crazy enough to even try.

~.~

It wouldn't be a Heterodyne escape if they didn't end up barricaded in a lab while Tony hummed happily behind them, building something that would either get them out or bring the building down around them - or both.

"Hyu'd tink madboyz vo iz tryink to make Jägers vould heff guards vorth fightink." Maxim grumbled. "Hy vouldn' take der hats even if dey _had_ hats."

They didn't even have proper death rays, just some sort of slug gun that was barely an annoyance to a Jäger. It would be more than an annoyance to Tony and his device, but Rogers was keeping them protected with a shield - not what Maxim would've though a proper Jäger weapon, but he'd changed his tune when Rogers had bounced it off an impossible angle to take out some of the minions who had them pinned down.

Still, it was the most fun Maxim had had in years. "Hey," he said to Rogers as a thought hit him, "dis iz de first time hyu getz to fight vit another Jäger, yah?"

Rogers brought the shield up to deflect another round from the guns, bouncing the slugs back close enough to their attackers to make them duck. Impressive. "You're the only Jäger I've ever met, so yes. Though I'm not so sure why you think _I'm_ one."

Maxim looked around reflexively, but Tony had knocked out the surveillance devices first thing and nobody was close enough to hear. He lowered his voice anyway. "Tony sez hyu vas a leedle guy before hyu take de Jägerbräu, yah? It hurtz like hell, enuff to drive hyu mad, but iz a _goot_ hurt becuz hyu ken feel it takink everyting dat makes hyu vorthy ov bein' a Jäger und mekkink it better." Rogers searched his face and then nodded sharply. Nobody who wasn't a Jäger could ever understand, not even the Heterodynes who'd created it. 

"Und ven hyu iz done hyu iz in de madness place. Hyu tinks hyu ken take on ennyone, und if hyu'z lucky dere's someone to fight." He smiled at a fond memory; new Jägers were notorious for starting bar fights - not the usual friendly one-on-one free for all, but one-on- _everyone_. Good times.

"Close enough," Rogers said, staring off at some distant memory of his own that didn't seem quite as good. "Wouldn't call it lucky, exactly."

Maxim nodded. "So hokay, hyu dun' got all de fun goodies-" he stretched out his hand to admire - and show off - his claws - "but it heppen like dat sometimez. Und ve all getz de better holfactory abilities." He nodded at Tony. "Heterodynes schmell goot, yez?"

"Oh," Rogers said, looking almost embarrassed. "Is _that_ what- never mind."

Maxim stared for a moment, then gave him a friendly punch in the arm that would've laid any non-Jäger flat. "Oh ho, hyu haz a crush on our Heterodyne!" He leaned in conspiratorially. "Dun' vorry, hyu izn't the first, und sometimez-"

"Stand back, it's coming through!" Tony shouted, much to Rogers' obvious relief.

Something long, sleek, and shiny burst through the wall, which then collapsed behind it. Maxim took one look and scowled, less than impressed. Shouldn't bombs be aimed at the _enemy_? "Hokay, hyu made a bomb… summoning… devize…" He trailed off as the "bomb" unfolded itself into the most amazing body armor he'd ever seen, flowing into place around Tony's body like controlled chaos. It should have made him as awkward as a Spark's first clank, but he moved like it was a part of him. And - Maxim blinked as Tony snapped off a shot at an incautious minion peering around the rubble - were those _death rays_ in the gauntlets?

Awestruck, Maxim dropped to one knee without thinking. "Hyu really _iz_ a Heterodyne."

Tony flipped up his visor and grinned down at him. "Even better. I'm Tony-fucking-Stark." He pulled Maxim to his feet smoothly. Maxim was impressed again - anyone could make a suit that could bounce even a Jäger hard enough to make a dent, but control like that took _talent_. "I don't know about you, but I'm ready to blow this joint."

Rogers moved smoothly into position beside him, shield ready; they'd obviously done this countless times before. It reminded him of Barry and Bill, and of Oggie and Dimo. Maxim bared his fangs in a grin that generations of _smarter_ minions had learned to run away from fast. "Ho _yezzz_."


	2. Chapter 2

"I nearly sat this one out," Fury said, standing in the doorway of the makeshift medical room Tony had commandeered, arms crossed and giving Tony his best _what am I supposed to do with you_ glare. "A simple extraction followed by a raid - what could go wrong? And then I remembered we were extracting _you_."

Fortunately Tony had developed an immunity to that look through long exposure. "Getting captured by the latest HYDRA-wannabe wasn't exactly my idea of a good time," he said, "but you have to admit that the extraction part went relatively smoothly." One mostly intact industrial park, one collapsed bioterrorist ring, and the recovery of stolen SHIELD and Stark Industries research (for which heads were going to _roll)_.

And one long-lost Jägermonster, who'd inexplicably decided that Tony himself was a long-lost Heterodyne. Sure, he'd heard all the stories of the Great Spark War and dreamed of rediscovering their lost science - or at least those parts that weren't outlawed by international treaties - but the idea that he might actually be something straight out of an old Heterodyne Boys movie? Or more worrying, _responsible_ for one?

As if following his thoughts, Fury cocked his head questioningly at Maxim, who was lying unconscious on the gurney behind Tony. The medical readouts were normal, assuming Steve as a baseline, and his injuries had already healed, but Tony was familiar enough with Steve's recovery process to know Maxim wouldn't just bounce back immediately after however long he'd been a prisoner. Or Jäger-sicle, Tony suspected, based on the notes and biological samples his captors had shown him. Despite that, Maxim had fought off his collapse until Tony had promised no one else would work on him. 

Tony could no more have denied him than he could've let anyone else work on the 'bots.

Not that he was going to let Fury know; he did have a reputation to uphold. "He followed me home," he quipped. "Can I keep him?"

Fury shook his head. "One of the most feared of all the pre-collapse constructs," he grumbled. "At least you had the good sense to keep him isolated. Do you have any idea what's going to happen if this gets out?"

"I'll say he's my bodyguard," Tony said dryly. "SI employee, unfortunate victim of the same people who grabbed me. You do seem to like that cover story."

"You're going to need one," Fury answered. "You think being Tony Stark makes you a target? That's nothing to being the Heterodyne."

"Assuming he's right about that."

Fury gave him a long slow look, armored head to feet and back again. "You're still in the suit. You've made my people nervous enough that they sent _me_ in to talk to you. If it turns out you're not, you think anyone's going to believe it?"

Tony wanted to pace but there wasn't enough room, not with the suit. Maybe he _should_ take it off. "They wouldn't let me anywhere near anything I could use as a tool," he said, a week's worth of built-up frustration pouring out. "Not your typical kidnappers-for-science. Nothing I could do to get myself out. I hate it when they're smart. I hate it even more when they block my rescue with _my_ stolen tech." 

He absently tried to run a hand through his hair and hit the helmet instead; flinched and fumbled for the manual release. He probably _did_ look like a typical madboy right now. It didn't help that Fury visibly relaxed once he got it off. "So yeah, maybe I'm a bit on edge, and maybe I'm a bit defensive of someone who helped _get me out_. So what if he's got some crazy ideas?" They _had_ to be crazy ideas. Never mind that something about it resonated in a way he really didn't want to think about.

Fury went silent long enough to be worrying; Tony had never known him to pass up a chance to puncture his ego. "The old Heterodynes were exactly the kind of threat to global security that SHIELD was created to handle," he said, watching Tony carefully. "There were enough rumors floating around at the end of the war that we included them when we were making contingency plans." He paused, his expression unreadable. "Some of them were designed by your father." 

Which meant, if Maxim was right… No. The day was weird enough already.

"We pulled one of them out for you when you announced you were Iron Man. Weapons designer invents a personal superweapon and practically declares himself outside the law? It didn't need much modification."

And _ouch._

"So yes, I think it's entirely possible. But do I think you are going to be a problem for SHIELD? No. I know you, and in this case - I trust you." 

"I'd have bet serious money I'd never hear you say that," Tony said. "Really. You could've made a fortune."

Fury gave him a long appraising look. "I'll let you take your monster home. Hell, he's not even close to being the strangest one of your strays," Fury said. "However if you hold another press conference and announce you're the Heterodyne, all bets are off."


	3. Chapter 3

Maxim followed the new Castle's voice to a kitchen containing more food than he'd seen in one place in longer than he'd like to think about. It even took him a moment to remember to thank the Castle, a dangerous lapse - _always be polite to the Castle_ ranking next to _if you lose your hat, it's a bad plan_ in Jäger lore. He was so distracted he almost didn't notice Rogers - _Steve_ , Maxim reminded himself; they were brothers now, after all - enter the room behind him. 

"Jarvis?" Steve asked, looking upwards the way new Jägers did before they'd gotten used to the idea that the Castle was everywhere, and that looking up was a guaranteed way to have it set off a trap under their feet. And then, of course, they looked down too much and had things dropped on their heads. Fun times. Maxim checked the floor and ceiling - this castle didn't _look_ like it had traps, but best to be sure. "Why did he just call you a castle?"

"Your pardon," the Castle said. "I may have neglected to introduce myself. My name is Jarvis, and I am an artificial intelligence created by Tony Stark. If there is anything you need at any time, please ask."

Neglected, ha. "Ho, yez. De old Heterodyne Kestle liked to surprize pipple too," Maxim said, grinning cheerfully. The world might have changed a lot, but Heterodynes were still the same.

Steve gave the ceiling a suspicious look. "Yes, I suppose it's only to be expected from something Tony created." 

Maxim gave up trying to make a decision. He grabbed a loaf of bread and an armful of whatever was closest, perfect for a classic Jäger sandwich. Steve gave him a very strange look and started to assemble something more like what non-Jägers would eat. 

Or new ones. "Hyu hazn't been a Jäger long, haz hyu?"

"Depends on how you count it," Steve said, and explained how Tony's father had been part of a team trying to make an army of super soldiers, starting with one undersized but eager volunteer. How the Jägerbräu had been lost when an enemy agent tried to steal it. Then a war, a crashed airship, and years spent in the ice. "Other people have tried, but I'm still the only successful one."

"Zo hyu iz still a new Jäger, und hyu didn't even haff enyvon to tell hyu vat it'z like." It was much too sad. No brothers - and very rare sisters - to welcome him as Jägerkin, one big family that would always, anywhere, have his back, who would understand him like nobody else could. He pushed aside the thought that _he_ didn't have any of that anymore either, and perked up at the one that took its place. "But iz hokay becauze now hyu haz _me._ "

~.~

Tony pushed back the goggles and set down the soldering iron, as satisfied as he could be given the circumstances. All the damage to the suit had been repaired, improvements had been made to systems that had been suboptimal, and the signal-jammer neutralizer - a smaller and more refined version of the device he'd created during his rescue - had survived every test he could throw at it.

That left only the non-technical problems to solve. He'd hacked SHIELD's preliminary reports; combined with what he'd observed, it was obvious there was more going on than just another group who'd gotten their hands on old HYDRA research. Someone was backing them, someone with the knowledge to give them tech that could counter his own. Add to that their approach to aquiring researchers - not to mention research subjects - and it was all getting annoyingly personal.

Speaking of research subjects. "Jarvis, what's the status of my newest houseguest?"

"Captain Rogers and Maxim have been bonding over elements of their shared physiology of which Rogers was previously unaware. Apparently one of the benefits is that anything is edible is also delicious." Jarvis paused, a perfectly timed beat. "The discussion of what constitutes 'edible' during a prolonged siege was particularly enlightening."

Tony blinked. "Yeah, not a conversation I want to have before breakfast."

"Or lunch, sir. It is now late afternoon."

"It is? Damn. How many calls from Pepper have I missed?"

"Three, sir, and she said not to tell you if you ask what time it is there. Shall I call her now?"

Which was Pepper-code for _I know you won't remember that you ought to ask_ , so he just nodded. If the CEO of Stark Industries dropped everything whenever he got in trouble…well. She appeared almost immediately, dressed for bed in an interchangeable hotel room. No clues there. "Tony! Are you all right?"

"Fine, nothing damaged but my pride. Bored. Frustrated. The in-cell entertainment was _definitely_ lacking."

Pepper gave him an assessing look and then nodded, satisfied. "I got the report from Phil. He said there was another prisoner but that I should talk to you first. Tony," she said, somewhere between puzzled and accusing - Tony couldn't remember the last time Coulson had kept her out of the loop - "what's going on?"

"Yeah, about that. Jarvis, do we have any pictures from the suit? Not of him fighting, but-" 

Jarvis had pulled up the first image the suit had captured, Maxim looking up at him like all his Christmases had come at once, kneeling like a medieval knight declaring his undying fealty. Tony had very carefully not been thinking about that moment. Up till then he'd dismissed most of what Maxim had said as drug-induced rambling, but - _you really are a Heterodyne_. In the rush of the invention-under-pressure high, it had all felt _right_.

"Tony?" Pepper asked, in her _defusing the Tony-explosive_ voice.

" _Not_ that." Jarvis pulled up another image, this one from somewhere in the Tower. "Right," Tony said, sending it to Pepper. "Don't know how much was in the report, but this is Maxim. Yes, he's purple. Yes, claws, fangs, everything's real. Official story is yet another try at the Super Soldier serum, and that he's one of ours. Yours." _Mine_. "Stark Industries employee, bodyguard, you know how to make it happen."

"And the unofficial story?"

"It's…" Tony paused; _classified_ was an insult to his phone's security, _complicated_ didn't begin to cover it. Pepper's eyes narrowed, his name forming on her lips. "…kind of a family thing."

That stopped her. She looked at him closely and frowned. "You _will_ tell me everything when I get back."

"Promise. Everything."

~.~

"Jarvis," Tony's voice carried clearly over the boiler-room clamor of steel on vibranium, "why does it sound like they're starting the next Battle of Manhattan in here?"

Steve spared a quick glance at the blast-resistant observation area of what had once been a small-scale weapons testing lab and now was, as Tony put it, the Avengers' playroom. Tony settled back with a look of eager interest as Jarvis filled him in: a demonstration of the offensive capabilities of the shield had turned into an education on Jäger fighting styles and weaponry. 

And it _was_ an education - Steve had thought he was good, but he'd never really gone toe-to-toe with anyone in his weight class before. Lapses in concentration that would've gone unnoticed by anyone else resulted in a sharp rap from the barbell that Maxim was using as a quarterstaff.

"Now ve show off, yah?" Maxim asked, with the barest twitch of a nod in Tony's direction. Without waiting for a response, he stepped back and began swinging the staff in a showy figure-eight pattern.

Steve watched him for a few moments. Disrupting the pattern would be easy; doing so in a way that would let him recover the shield was trickier. After considering the angles, he flicked the shield, bouncing it off the floor like a rock skipping across a pond. Steve didn't pay much attention to where the staff ended up as he dove into a roll to intercept the shield, not too far off from where he'd predicted.

" _Goot_ von!" Maxim said, with a smile that was all fangs. "Und now hyu findz out how ve fightz _unarmed_."

Maxim moved in hard and fast, not bothering to pull his punches. Steve found it difficult to adjust; the shield was awkward at that range, and he was considering dropping it when he saw an unexpected opening. He swung the shield, hard, and Maxim almost dodged it, flying through the air to crash hard on the floor. Steve barely had time to notice that he'd somehow landed right next to the staff before he was on his feet again and charging, staff raised for an overhead strike. Steve flung the shield out of reflex. Maxim dropped the staff down into a defensive position and gave it a twist just as the shield hit. It ricochetted off the walls and back to him, where he snatched it out of the air one-handed.

"Whoa," Tony said. "Did I just see that? Jarvis, tell me you got all the angles."

"I give," Steve said, raising his hands with a smile that was both chagrined and appreciative - he'd been set up from that first open shot and he'd fallen for it. Maxim grinned and struck a pose, shield raised and staff at the ready. He looked like he'd just stepped off the cover of _Weird Tales_ , and Steve's drawing fingers twitched with the urge to do it justice. "Wish I had my sketchbook," he said absently.

"Yez?" Maxim asked, his grin shifting from fierce to teasing, and his body language changing to match. "Hyu vantz to draw me like de Parisian gurls?"

Tony gave them a very odd look, then laughed. "Well, I don't want to draw you," he said, "but I would _love_ to design a weapon for you. Anyone who can swing a solid steel bar around like that…" 

Maxim gave the bar a twirl and looked at it appraisingly. "Iz nize, but Hy likez svords better."

"Oh, really?" Tony's voice shifted into the tone that promised another marathon session in the lab. "Well, I've never designed a sword, but I'm sure I can come up with something. Traditional metals won't do, it'll have to be able to stand up to the shield…"

"Tomorrow," Steve said firmly. "I don't know about you, but I could eat -" He nearly finished with _a horse_ , but wasn't sure Maxim would know it was a joke.

"Oh, right. Food," Tony said, and then snapped his fingers. "Right. _You_ ," he said, pointing at Maxim, "need to meet everyone, and you _both_ need to get caught up on pop culture. So. Pizza, movie night. I'll bring the popcorn."

~.~

_Be a good girl or the Jägermonsters will eat you._

"Nat?" Clint said, the _are you all right with this?_ going unspoken. 

Natasha shrugged. "It's why we're here." _Tony invited us. Fury gave us an assignment._ Clint was one of the few people who knew how much of this was personal for her. Sparky social scientists, refugees from the final battle over the Heterodyne territories, had found post-revolution Russia fertile ground for their theories. The Red Room had been only one of the results.

Natasha's first thought on seeing her target was that he was a lot more human-looking than she'd expected, and - "He's wearing your shirt," she said to Clint, momentarily distracted - which was, of course, why he hadn't warned her. 

"Yeah," Clint said. "Cap asked if he could borrow it. Looks good on him." He smirked. "Purple is definitely his color."

Natasha rolled her eyes at him, but the smile she let slip was empty of subtext.

Maxim caught that smile and answered it with one she'd seen many times before from people who hadn't bothered to look past her surface charms. That changed when Steve introduced them both as being his teammates; she could practically see him re-examining every move they'd made since they walked in the room. "Hyu fight, yez?"

"We're a team. We all fight," she answered.

She wasn't expecting his look of attraction to transform into awed respect; it wasn't a typical response. She was saved from having to answer when his head went up, nostrils flaring. "Someting schmellz _goot_."

The elevator opened to reveal Bruce, Tony, and a large stack of boxes. Steve automatically moved in to help. 

"Pizza," Clint said. "Add beer and you've covered the four basic food groups: bread, grease, and meat."

"And we have beer," Tony said. "And everyone else is here, so - Bruce, meet Maxim. Maxim, Bruce. He's a fellow member of the chromatically enhanced club. Part time, that is."

Bruce shot Tony a fondly exasperated look. "Ah, what Tony is trying to say is that I've had my own encounter with the Super Soldier serum. It… didn't go so well." He fidgeted with his glasses. "I'd really like to talk to you, maybe run some tests. With your permission, of course."

Maxim shot a quick look at Tony, who nodded. "Sure, but no poking at the science experiments during movie night. That's my job."

Clint and Natasha shared a look of their own, which Tony caught. He picked up a slice of pizza and drifted over to her. "I know that look. You used to aim it at me, back when you were Fury's spy." Despite the words and the history behind them, there was no heat in his tone.

She shrugged. "He wants an evaluation. You knew it had to happen." 

"And are you also re-evaluating me?" There was just the hint of uncertainty under his public show of indifference.

"Why?" she asked, mock-puzzled. "We haven't learned anything that would change my initial evaluation." He grinned as the faint emphasis on _initial_ registered, not the public smarter-than-everyone smirk but the real one that only showed when he remembered he had a team willing to back him up. That hadn't been the finest moment for either of them. She'd been taken in by his public persona, and it did nothing to salve her professional pride when she learned that he was intentionally doing his best to live down to that reputation.

Apparently satisfied, he moved to the center of the room and announced, "Right, if everyone's ready, let's get started. This movie was inspired by the old Saturday morning serials - Buck Rogers, Heterodyne Boys, Captain America - starring our very own Capsicle -" Steve grimaced, and Tony smirked at him. "But I'm not that cruel. No, in honor of the newest member of our merry band, we're watching Spielberg's tribute to the Heterodyne Boys. Mad Sparks, damsels in distress, mystical artifacts from the depths of time. Not as good as the first or third, and we'll all pretend the fourth never happened."

Steve leaned over to say something to an obviously puzzled Maxim. He grinned suddenly, "Ho, yez, like der travelling Heterodyne showz. Vun time dey set vun up in de town sqvare vile ve vas up on de gallows. Best seat in de houze."

Tony stopped and stared, trying to decide if he was serious. Natasha didn't have any doubts. "OK, you know what? I'm not even going to ask. Jarvis, hit the lights."

Natasha found herself seated between Tony and Clint, which wasn't a coincidence - the sofa they were on didn't have the best view of the screen, but it did have the best view of the room's other occupants. She hadn't intended to watch the movie itself until a piercing scream drew her attention. Indiana Jones - she knew her American pop culture well enough to recognize him - was rescuing a screaming blonde from some sort of Sparky contraption in the Paris sewers. _That_ brought back memories. But the actress - "That's supposed to be a Russian accent?" she scoffed.

Tony grimaced. "Oh. Willie. Yeah, she's pretending to be a refugee Russian Countess. I, ah, forgot about that part of it." He sounded sincerely apologetic.

She gave him a sidelong look. "Despite the rumors, that really was before my time," she said, deadpan. "Just warn me if she's going to scream like that again."

"She does that a lot," Clint said. "I liked Marion better."

"Who doesn't?" Tony said. Steve shot them both a quelling look and they subsided.

On screen, Jones traced rumors of an ancient artifact through various countries, picking up a sidekick along the way - a Jäger in the style of the Heterodyne Boys stories, there mostly for comic relief. Maxim laughed at that; "Ve iz scary, yez? But if pipple tink ve iz fonny, dey forget dey ought to be scared. Until it iz too late." Natasha couldn't argue, given her own skill in being deceptively harmless.

The annoying Willie was revealed to be the Mad Spark's daughter, with no improvement in her accent, but the actor playing her father had done his homework; even his Russian had a trace of Mechanicsburg. Natasha didn't think her reaction showed, but Tony picked a bad time to be observant. "You're not just studying him because Fury told you to, are you?"

She shook her head, as much a denial of her thoughts as it was an answer. It was the past, and she had dealt with it. But - he was her teammate. He deserved more. "Where I'm from, the worst nightmares have Mechanicsburg accents. I saw the footage from your escape. You think you can control him?"

Tony gave that the consideration he usually reserved for technical puzzles. "Seriously? I suspect I could. Because hey, surprise, my family's been in the mad science business for a lot longer than I knew. But you know, when you think about it, who's more dangerous - the weapon or the weapon's designer?"

"You're not exactly helping your cause," she said, but some of the tension she'd been holding started to lift. Objectively speaking, Maxim wasn't all that different from Steve - not even, if she were honest, in the way they fought. Maxim wasn't even close to being like the Hulk, and she'd come to terms with that.

"If anyone around here is a Mechanicsburg nightmare, it's me. And you know me. So…" He spread his hands and shrugged. "The conclusion is obvious."

"Right," she said, and if it wasn't her usual level of deadpan snark it was close. "I'll just tell Phil I may need to borrow his taser again."


	4. Chapter 4

**Notes for the Chapter:**

> No Winter Soldier spoilers. And I will try to update a bit more frequently!

“That cannot possibly be a Muse.” Tony gave the CEO of HeliosTech the same look small children gave to incompetent magicians. “Unless you’ve managed to turn up a long-lost Nazi cache of looted art, and I think Pepper would have something to say about me forgetting she’d told me if you had.”

Pepper looked past Tony and caught her breath. Seated on a small stage at the focal point of the Silicon Valley History Museum’s newest (and Stark Industries-sponsored) exhibit hall was a mechanical construct - a woman, wearing flowing robes like a Greek statue, gold-trimmed to match the filigree on her porcelain enamel body. But “construct” didn’t begin to do her justice - even if she wasn’t a Muse, Pepper thought, she was as much a work of art as any of Van Rijn’s legendary masterworks. As the centerpiece of a collection showcasing the history of thinking machines, she was perfect. 

Not that Pepper was going to admit that to Lawrence Morgan.

Despite the prominence of the Stark name on the donor list, the SI presence in the exhibits themselves was minimal, aside from the obligatory fighting clanks from the early days of Stark Mechanicals and a brief mention of Tony’s AI work at MIT. SI’s expansion into Silicon Valley’s market had been inevitable, but Pepper’s message here was that they could all work together.

Morgan, however, hadn’t seen it that way. He wanted HeliosTech to be the leader in robotics technology, to the point of buying companies when he couldn’t poach their top engineers. But the trouble with talent acquisitions, he was discovering, was that there was nothing stopping the talent from leaving when a better option came along.

Plus Pepper strongly suspected him of being behind recent attempts to steal the designs for Tony’s ’bots, and that was unforgivable.

“The Paris Muses are still lost,” she said, faking a skepticism she didn’t feel, “but this wouldn’t be the first replica I’ve seen.” 

“Can a replica do this?” Morgan asked. He pushed his way past the onlookers to the side of the stage. “Attention everyone,” he announced, as soft music began to play. “I present to you Tinka, the Muse of Dance.” 

Pepper had seen some of the best dancers in the world, but nothing compared to this. Every move was perfect - not the soulless perfection of machinery, but the grace and elegance of a true artist. The legends had said they were sources of inspiration, and Pepper could believe it. She found herself moving slightly to the music as Tinka brought to mind memories of childhood dance lessons, and for a moment she almost thought the Muse was looking on at her with approval.

~.~

Dancing Muses were nice enough, Kari thought, but the main reason to see a Stark exhibition was for things that could go boom. And the replica vintage fighting clank - over six feet of polished brass and copper, with cutaways to show the gears and pistons - _definitely_ qualified.

“Impressive,” Tory said, sizing it up, “but how hard could it really be to take it out? It can’t be that smart, not just running on clockwork.”

“Iz not schmart, no, but iz verry hard to kill.”

Kari turned to see Stark’s bodyguard giving the clank a grin that probably would’ve been just as predatory _without_ the fangs. Which meant - “You mean Stark’s got a _working_ version?”

“And you’ve fought one?” Tory asked. “Think he’d let us borrow it?”

“Um, dat vaz before,” he said, ducking his head sheepishly. 

“Right,” Tory said, because tact was not in his vocabulary. “Before - ow!” He rubbed his arm where Kari had punched him. _Before he’d run afoul of the latest mad scientist’s attempt to make a super soldier._ Stark’s press release had been oddly vague about his past in a way that Kari thought practically screamed _secret agent_ , though Tory was more fond of the fringe theory that he’d been one of the soldiers Hydra had captured during WWII. 

“Iz hokay. Hy vas vun of de lucky vuns - Hy _lived_. Und mebbe Hy ken’t be so schneaky now, but dere’s advantages.” His hand brushed the sachel slung casually over his shoulder, which Kari suddenly realized had to be the portable version of the Iron Man suit.

Tory had noticed it too. “I’d wondered why Iron Man would need a bodyguard,” he said, and Kari knew he was itching to get a peek at it just as much as she was.

“Ha, vell, hyu know H- Starks. Alvays finding trouble, yah?”

Kari was momentarily distracted, considering the fun they could have working with Tony Stark and the suit. _Not going to happen,_ she thought, but - “So, clanks. Hard to kill?” she prompted.

He nodded. “Yah. Hyu gotz to get in close to take dem down. Gunz don’t do much unless hyu getz verry lucky. But unless somevun vit a brain iz behind dem, hyu ken outthink dem, eazy.”

“So if guns don’t work…?” Tory asked.

“Hy like svords. Get in close, take out de joints,” Maxim said, miming a swing to the back of its knee and a follow-through to an elbow.

Tory and Kari shared a look. “He knows how they fight,” he said.

“And Grant could build one…”

“If we can distract him from building his own Muse. He was still going on about balance calculations when I left.”

“ _Swords_ ,” she said. “He’ll do it.” She looked at the clank’s internal mechanisms. Even given it was a non-functioning plastic replica, there were some obvious gaps. She could design her own weapons systems, of course, but if they wanted it to be authentic… “Think we could get Stark to give us the full specs?”

“Why not? It’s for science!”

~.~

Pepper spotted a familiar face watching the Muse and her eyes narrowed. “Hello, Phil. Should I be glad you could make it after all, or is this a professional visit?”

Up to now the exhibit had been a success on all fronts. She’d made some useful contacts, overheard conversations that indicated Morgan’s ploy was more transparent than he thought, and even had time to talk to one of the women who Howard had hired straight out of Bletchley Park - say what you would about him, he respected talent when he saw it, and had been one of the few people with the clearance to know what all those women had been doing during the war along with the foresight to snatch them up when everyone else expected them to go back to the kitchen. 

“Professional, I’m afraid. It shouldn’t affect you -” Her eyebrows went up at this.“No, really. We just have some questions about where this lovely lady came from.”

“Knowing Morgan, she ‘fell off the back of a truck.’”

Deadpan as ever, Phil said, “Let’s just say I’m looking for that truck.”

Tony came up then, wearing his _don’t mind me, nothing interesting here_ smile. “Agent. Decided to crash my party?” He turned to Pepper in a fake aside, “He is crashing my party, right?”

“ _Phil_ had an invitation,” Pepper said pointedly.

“Are we expecting trouble?” Tony asked.

“No,” Phil said, as Pepper answered, “Probably.”

Tony looked between them. “Right.” He took out his phone and shot a look at Maxim, who pulled himself away from a small crowd gathered around the clank display and started to make his way across the room.

“Nothing suspicious… no, wait…”

Something hit the roof with a loud thump. Heads went up around the room, more than a few of them bracing themselves as if they expected aftershocks. With a shriek of tortured metal, the skylight vanished, raining debris around the stage - _but no glass_ , was Pepper’s first distracted thought, _so they did make it shatter-proof after all._ A large metal shape, similar to Tony’s suit, landed next to the Muse and announced, “Victor von Doom, last true heir of the Storm King, summons you. You will obey.”

“Doombot,” Tony said. Maxim slid the portable suit across the floor to stop at Tony’s feet. It unfolded, but not fast enough. “Dammit…”

Tinka stopped dancing and cocked her head, considering. Her eyes flashed, arc-reactor blue. “I think not.” She touched the Doombot on the shoulder gently and blue lightning crackled around them.

The Doombot collapsed to the ground. Tony stared at it as the suit finished assembling, then, “There’s more on the roof,” he said, and took off through the ceiling. Maxim touched one hand to his ear, listening to a report from Tony, then turned to the trio that had followed him with a shout of “Ve _hunt_ ”. The four of them ran for the door; Pepper just hoped they all knew what they were doing. 

Phil, meanwhile, was waving the rest of the crowd back. “Reinforcements are already on the way,” he said to Pepper, and grimaced. “Not that I was expecting anything like this, but I won’t blame you if you don’t believe me.”

“We’ll talk later,” Pepper said. She turned to Tinka, whose hair and gown were scorched tatters but who seemed otherwise undamaged. “Are you all right?”

The Muse was still staring at the Doombot, one hand raised to her mouth. “It can’t be from my Storm King. The Castle…”, she said softly, sounding lost and confused. “It was mad. We tried to help it, but it just wouldn’t listen.” Her voice caught. “It… it killed him. It killed them all. It… _oh_.” 

She wobbled then, and Phil barely managed to catch her before she toppled off the stage. He frowned as he set her down, a look that Pepper recognized. Maybe this wasn’t the best time, but she had to know. “Phil. What are you not telling me?”

He sighed, pulled out a tablet, and brought up a clipping from an old newspaper. A smiling blonde woman stood with her arm around a serious looking young man. Something about her seemed familiar, but Pepper put that aside and zoomed in to the figure behind them. Even given the fuzziness of the image, it was obviously the same Muse.

“The Heterodyne Princess and her Storm King, three days before they entered Castle Heterodyne. That’s the last anyone saw of any of them.”

Pepper looked at her and then back at Phil. “If she really came from the Castle…”

Phil looked grim. “Then somebody has found a way to get in.”


	5. Chapter 5

Jenka perched in the darkness on a ledge with a good view of the loading docks of Stark Tower. She still didn’t know if she needed to be planning a rescue or not, or even if Maxim had received the message she’d slipped into a mail cart two days ago. No name, just the location - he’d know to come at night when it was deserted - but the Jäger sigil was enough to betray her if he had been captured by someone who knew what he was. She’d give him one more night, she thought, before she went in after him.

It was well past midnight when the door finally opened and Maxim stepped out. He looked around and sniffed the air, but she’d chosen her spot to be high enough that Jäger senses wouldn’t be able to detect her, risking the fact that if they were looking with anything more sophisticated it was already too late. He didn’t act like the bait in a trap, any more than he had when he’d charged into battle against the Latverian clanks, in front of countless other idiots with cameras. Out there having fun, as if it didn’t even matter if he got caught, when she’d thought he was _dead_ …

“Hyu _eediot_ …” she growled, dropping to the ground behind him. 

Before she could blink, she found herself wrapped in a hug that would’ve been bone-crushing on anyone but a Jäger. “Jenka?” he asked, voice muffled against her shoulder. “Hy couldn’t believe it. Hy thought Hy vas de only vun left.” He pulled back to look at her. “Der vas a mob, und an avalanche…” 

“I know,” she said, softening, and hugged him back just as fiercely. “Dimo and Oggie told me.” They’d made the mistake of getting too close to a town that still remembered the _old_ Heterodynes, even more than a generation after Mechanicsburg had finally fallen. “They tried to find hyu, but the mob was too close behind them.”

“Dey made it?” Maxim looked around as if expecting a pack of Jägers to just appear in the middle of New York. She felt irrationally angry - he couldn’t have known that they’d all agreed they had to split up after they’d lost him. Dimo and the others who, like him, could never be mistaken for anything but a Jäger had pushed hardest for the separation. Jenka and the ones who could blend in had hated it, but it made too much sense - after all, everyone _knew_ Jägers travelled in packs.

“Yah. They’re in _hiding_. Ve all are. Except _hyu_. Vat did hyu think hyu were doing?” she asked, shoving him for emphasis until he hit the wall behind them. “Ve were the _wild_ Jägers. The last vunz not to abandon the search. Ve don’t just fight for any Spark vit a nize suit!”

Maxim leaned against the wall as if he’d always meant to be there and grinned like a cat with a canary. “Unless dey iz a Heterodyne.”

Jenka went absolutely still. _Impossible_. She pulled back slowly and tapped him on the forehead with a clawed finger. “Hyu iz still frozen in der brain.”

He shook his head. “His great-grandmama had a locket vit a picture of Bill - and _her_ ,” he added in an undertone.

“Anyone could have a locket.”

“Und his papa - he made a Jäger.”

That made her stop. Nobody else had ever made a Jäger. They’d tried… “Wait - they called you a Super Soldier. Like Captain America.”

He made a show of buffing his claws on his chest; if he’d looked smug before, now he was insufferable. “Schneaky, yah?”

“… we have a new brother?”

~.~

“Sir,” Jarvis said, “Maxim has requested permission to bring a guest up to meet you.”

“Show me,” Tony said. The nearest screen sprang to life with clips of the tower’s security footage. At first glance Maxim’s companion looked like a typical New York goth, dressed head to toe in black with a surplus of buckles and zippers - though to Tony’s eye it tipped more towards the Black Widow-practical end of the spectrum - unnaturally pale hair and skin, claws… “That’s not cosmetic, is it.”

“Visual analysis suggests her physiology is consistent with the other enhanced members of the household, sir.” A shot of her landing on his loading dock was overlaid with numbers indicating the forces involved and the estimated distance travelled.

“Any idea who she is?” he asked, glancing at the blank area of the screen which ought to be filling up with information.

“There are no records matching her description in any of the databases to which I currently have access.”

“Huh.” Tony watched the footage from the loading dock loop through and restart. “Sure, let them up.”

 

Tony was waiting by the elevator when it opened. Jenka stepped out and took a deep breath; Maxim, hovering nervously behind her, seemed to be holding his. Tony still had no clue what was special about his biochemistry, but when even the Hulk said he smelled good, there had to be _something_.

“Hokay, not _just_ a Spark with a nize suit,” she said, in a tone as much teasing as awed. Maxim visibly relaxed, and Jenka gave him a sidelong glance that seemed fondly indulgent. 

“Of course not,” he said. “You left out philanthropist - I’m thinking of opening the Tony Stark Home for Wayward Super Soldiers. What do you think?”

Jenka’s mouth quirked up in a smile. “Good idea. Iz - it’s harder than it looks, keeping these idiots out of trouble. Und iz your job anyway.”

Tony paused, serious for a moment. “You do know I’m not about to announce that I’m a Heterodyne. I’ve got enough of my own family history to live down.”

“I know who you are, Mr Stark,” she said.

“Tony,” he corrected.

She nodded confirmation. “That vas all a long time ago. The Castle is dead, ve are all hiding, but -” she tipped her head in Maxim’s direction. “He says you have a locket…?”

~.~

Jenka approved of Stark’s library. It was obviously designed more for comfort than to impress, with well-worn books lining the shelves. Despite the hour it was occupied; their entrance startled a tousled-haired man who’d obviously been drowsing in one of the comfortable chairs. He stood up, fumbling for his book and then for his glasses.

Maxim stepped forward to introduce them. “Jenka, meet Bruce Banner, very schmott guy who iz sometimes der Hulk.”

Sometimes? Jenka took a deep breath. Faint, but definitely a Jäger. Bruce glanced away from them uncomfortably for a moment, before looking back up and holding out his hand. “Pleased to meet you,” he said.

Jenka took his hand and then impulsively pulled him into a hug. What could it be like, being Jäger and not even knowing? “Is okay. Hyu are not alone anymore.”

“Ah… thanks?” Bruce said, as she pulled away from him. He looked shocked, like he’d never been hugged by a pretty girl before, which was a shame - he was rather cute in this form, and she’d heard impressive tales of the other.

She smiled at him as Maxim led her to where the locket had been mounted and framed to show off the portraits of Bill and Lucrezia. She recognized Barry’s artistry - despite the size, they were so detailed as to be almost lifelike. “I miss them so much,” she said, and if she was sniffling, well, Bruce and Tony were carefully not watching. Maxim put one arm over her shoulders and pulled her close. “Bill and Barry, and little Klaus Barry -” Bill’s little boy had been killed in the attack on the castle. He’d been the last known Heterodyne heir, which was one of many reasons why Tony Stark came as such a surprise. “And even _her_.” Bill had loved Lucrezia madly, after all, even if none of them had ever been quite sure why. “Do hyu think…” she said, and had to stop for a moment. “If ve didn’t hate her so much, would ve have protected them better?”

“Der vas nothing ve could do,” Maxim said. “Hyu know that. She vas alone in her lab, und vhatever attacked us came through there. But she must haff survived - there vas a daughter.” He showed her a framed sepia-toned photograph. “Dis iz Agatha. She vas a student at TPU and came here after it vas attacked. Took her husband’s name ven she got married, but -” he shrugged. “Vasn’t a good time to be a Heterodyne, if she’d even known.”

Nobody knew what the fake Heterodyne girl had done once she’d gone into the castle, only that when it died it had taken half the Sparks of Europe with it. Whether people believed she was a real Heterodyne who’d reverted to type, or knew she was a fake, they tended to blame Bill and Barry for not being there to stop her.

“I wonder…” Jenka said. The locket was just clipped into place and came away easily. The front was the familiar trilobite design. She closed her eyes and let long-unused muscle memory take over, clawed fingertips finding the recesses in the curves and moving through the common locking sequences. There was a faint click after the second try.

When she opened it again, the portraits swung out to reveal a pair of hidden compartments, filled with tightly-packed gears and crystals.

Bruce and Tony, who had come over to watch while she’d been trying to open it, peered inside. “Do you think there was a message recorded in there?” Bruce asked.

“I don’t know,” Tony said. “But I can find out.”

~.~

Bruce followed as Tony and the Jägers headed for the lab, partially out of curiosity but mostly because the number of people who didn’t flinch once they knew about the Other Guy could be counted on one hand, and none of them had ever been a sympathetic and attractive young woman. _Jäger_ , he corrected himself. Despite appearances, this was someone who, centuries back, had willingly chosen to undergo a process that could produce anything from Steve Rogers to the Other Guy.

“You seem a lot more comfortable with modern technology than Maxim,” he said, which wasn’t really what he wanted to ask but was the first neutral topic to come to mind.

“Yah, I’m one of the ‘lucky’ ones,” she said, with a guilty look at Maxim. ”I didn’t have to live in a cave, or worse.”

“I’ve done that,” he said diffidently. “Caves have their advantages - peaceful, isolated.” Totally deadpan, he added, “Really, I think everyone will be doing it in the future,” and got a hint of a smile in return.

Tony started clearing away a space on one of his workstations. “So how many more of you are there?” he asked. “Am I going to have a small army turn up on my doorstep?”

Maxim looked to Jenka, who shook her head slightly. He looked resigned, and Tony looked puzzled. “You’re the only ones left?”

“No,” Jenka said, “but they don’t know who you are.” Jenka paused, frowning, as if not sure what she should say. After Maxim gave her an encouraging nod, she took a deep breath and began, “Even when we had Heterodynes to avenge us, we were hunted. Villagers want to kill us, generals want to use us, Sparks want to take us apart.”

“Story of my life,” Bruce said, under his breath.

Jenka reached over and squeezed his hand. “It got worse once we didn’t have their protection. There weren’t as many generals or Sparks after the Castle fell, but there were a lot of angry villagers. We’re hard to kill, but harder to take alive, so if they went to that much trouble it usually meant we were being used as bait. So the generals made a rule - no rescues without a plan.”

“Und Jenka makes der plans,” Maxim added, in the tone of someone reciting a hard-earned lesson. He leaned towards Bruce and added, in a conspiratorial whisper, “Most of us aren’t so good vit the plans.”

Bruce turned a mock-innocent look on Tony. “And are Heterodynes any better?”

“Not really. Dot’z vhy we haff generals.”

“Dummy, make yourself useful,” Tony said. “My hands are full, so flip them off for me, okay?” The ’bot’s camera shifted between the three of them as it let out a confused chirp.

“And if we still had generals, I’d report this to them,” Jenka said, pulling everyone’s attention back to her. “There is a signal to send us back to the Castle. But nobody ever thought the Heterodyne _wouldn’t_ go there; any other message would have to be delivered in person.”

“Huh,” Tony said, which Bruce recognized as _there is another solution to this problem, and I will find it_. He set the locket down on the newly-cleared table. “Jarvis, light it up. Let’s see what we’ve got here.”

~.~

If Jenka closed her eyes she could almost believe she was in a lab back at the Castle. Waiting around because their Heterodyne needed lab minions was never anyone’s favorite task, but they’d found ways to fill the time - sharing battle stories, wagering on whether it would be a new weapon that they’d get to test or some other strange device. There was none of the latter now - Tony was confident it wasn’t a weapon, and it wasn’t likely he’d call on them to be test subjects.

And in the old days there would never have been a Jäger Spark like Bruce, who was far more interested in the Muse they’d been protecting than the fight itself. Jenka didn’t really care if it was real or not. She had clank trouble of her own; the one Tony had called Dummy, who had been banished from his end of the lab for being too clumsy to help with anything so fragile, had discovered the decorative fastenings on her clothes and apparently found them fascinating. She was trying to work out where to look to stare it down when something Bruce said caught her attention.

“…wait, she came from the Castle?”

Bruce nodded. “We’re fairly certain, yes, but we won’t know for sure until she’s recharged. I’ve done the analysis on the power curve and it should only take a few more days.” With a wry grin, he added, “But I can see why so many of them were destroyed - whatever’s powering her is more advanced than I’d expect from that era. The temptation to just crack the case to see what’s inside…” For a moment he got the look of unstoppable curiosity that typified Sparks, but then he shook his head and it faded.

“I don’t care how she works, I just want to talk to her. I want to know what they did to our Castle.” She hadn’t realized how much it still bothered her not to know, even after all this time.

“Oh,” he said, as if suddenly realizing something obvious, “you were there too.”

“We saw the Castle die,” she said. “We didn’t see what happened before - we weren’t allowed in the town until the Heterodynes returned.”

She had to explain, then, the deal that they’d made with Baron Wulfenbach when he’d reappeared a few years after Bill and Barry had disappeared. “They’d been friends, so we trusted him to hold off the angry villagers - or at least make them think twice - but his goal was to keep the peace. If he’d meant to search for them, he’d have let us keep the town ready for their return - he’d have let us _hunt_. But he had allies who wouldn’t mind if the Boys stayed lost if it meant they never had to worry about the _old_ Heterodynes again.” It had been the only choice they could make, and yet it still felt like betrayal. More so now that she knew there’d been a Heterodyne heir to find.

Maxim was telling how some of them - _not enough_ \- had split off from the pack to carry on the search when she felt her hat being lifted off her head. Without thinking, she spun around and grabbed Dummy around what she’d decided was its neck.

“Becauze hyu iz a Heterodyne clank, Hy vill giff you a warning,” she growled. “ _Let. Go. Of. The. Hat._ ”

The clank’s motors whined as it tried to pull back. Out of the corner of her eye she saw Tony look up, unperturbed. “Dummy, listen to the lady. Let go of the hat.”

Dummy let go and scurried away to hide behind Bruce. Jenka grabbed her hat as the world snapped back to normal. _Idiot_ , she thought, shaken; it had been decades since she’d let her control slip like that. _This is not the Castle, and outside they are still just one step away from being angry villagers._

Only Bruce seemed to be concerned. Maxim was amused, and Tony was curious. “What is it with the hats, anyway?”

“And how do you just… turn it off like that?” Bruce asked.

“Hy-“ Jenka stopped, and forced the accent down with an effort. “I got my hat back,” she said, confused.

Maxim clarified. “He iz still a baby Jäger, and when he goes to der madness place, he goes _all de vay._ ”

“Oh…?” she said, frowning. And then _Oh. That explains Harlem._ Although he hadn’t reacted when _she’d_ gone into the madness place, so his control couldn’t be that bad. “Lots of practice, and a pack of Jägerkin to sit on you until you get it right,” she said, though the three of them - or four, she recalled - barely counted as a pack. From Maxim’s look, he was probably thinking the same thing.

“Right,” Tony said, as the silence started to get uncomfortable. “But about the hat. Sure, everyone laughed when Indy’s sidekick went off like that, but that’s the movies. I know you take them from the heads of your defeated enemies…”

“Or you can be sneaky,” Jenka said, with a sidelong glance at Bruce. It had been so long since she’d had a chance to brag. “I got my first hat from a Smoke Knight who was sneaking into the Castle. Swapped it for a jester’s cap. She was good, but I’m better - she didn’t notice the switch, but she still nearly made it past the guards before she started jingling.” 

Tony gave her a considering look. “I’m not sure if you’d be Natasha’s best friend or worst nightmare,” he said, “but either way I’d want to be behind blast shields when you meet.” At her puzzled response he just waved them on. “Never mind. Hats.”

“Taking an enemy’s hat like that is good,” Maxim confirmed, “but taking a Jäger’s hat iz a challenge. Or an insult, if vun of uz does it. Iz saying hyu didn’t earn it.”

Jenka nodded. “You fought more duels over your hat than anyone.”

“Oh, yah.” He smiled, reminiscing. “Me und Erich ver baby Jägers, und Andrei had lost his. So ven ve saw a squad of der Baron’s elite cavalry, vell…”

“They did have very nice hats.” Not as fancy as some, but highly recognizable. And a perfect color match to Maxim, which wasn’t always a factor in hat selection but didn’t hurt.

“So ve charge, and ven they see three bare-headed Jägers, dey all throw their hats to the ground and run. Erich izn’t sure iz hokay, but I said, anyvun who thinks dat isn’t a good vay to get a hat is velcome to take it off my head.” He sighed. “Hy really miss that hat.”

Tony gave them a fondly exasperated look that was _very_ familiar. “OK. So now that you’ve all thoroughly traumatized my robot, I think I’ve got this working. For whatever that’s worth.”

~.~

Tony’s first actual Heterodyne artifact - if you didn’t count any of the interesting Stark Mechanicals devices that had never made it to production - was a disappointment. The half of it that had looked like it had been kludged together from a self-winding watch turned out to be exactly that, but the rest of it…

“It’s a machine that goes ‘ping’,” he said, which got an eyeroll from Bruce. “Seriously, I’ve spent most of this time tracing circuits to be sure. Power goes in, nothing I can measure comes out. And why a machine with no obvious effect would need a continuous power supply…” He looked at the Jägers apologetically. “So if you were expecting a message, I’m sorry, but I don’t think this is it.”

Bruce picked it up. “Odd… are you sure it’s not doing anything? It feels - I don’t know, not warm -”

“Because I would totally have failed to notice if it was producing heat…”

Maxim said, “Let me try,” took it from Bruce, and then looked startled. “Jenka,” he said, more serious than Tony had ever seen him. He dropped it in her hand. She frowned and said something in a language Tony didn’t recognize.

He cocked an eyebrow. “Right, want to share with the rest of the class?”

They shared a look, then Maxim said, “Hy should do it. They know me.” Jenka nodded and handed the locket back to him. He scratched a shallow cut on the back of his hand. It should have healed almost immediately, but - it didn’t. _Odd_.

“Hyu haff heard ve never let anyone vurk on uz but Heterodynes? Dis is vy.”

Tony found himself tapping the arc reactor and forced his hand to be still. His father’s records included some of Steve’s medical reports from the rare times when he’d been seriously injured in battle that Tony really didn’t want to think about. “What about drugs - anesthetics?”

Maxim nodded. “They vork. Everyting slowz down,” he said darkly. “Iz vun of our most guarded secrets. It makes uz easier to kill. It should _never_ have been taken out of der Kestle.”

And someone had put that into a locket and given it to his great-grandmother to wear. If it had that effect on Jägers, what did it do to Sparks? Tony suddenly didn’t want to be anywhere near it.

Satisfied the point had been made, Maxim set the locket down. Bruce made an abortive grab to pick it up and then had second thoughts. “What else does it do? Would it…” He waved vaguely. Other Guy, right.

Maxim considered that for a moment and then shrugged. “Ven Hy needed it, Hy vasn't thinking about anyting elze.”

Jenka nodded and added, “They never told us how it works, but -” she shot a look at Tony, and he nodded, guessing what she intended - “I can help you find out.”


	6. Chapter 6

> Jenka sat on the top of the Castle’s South Tower - which the Castle had indulgently adjusted to be both its highest point _and_ the farthest from Lucrezia’s labs by any possible measure - and watched the sun set over the mountains. Somewhere out there Bill and Barry were being embarrassingly heroic, which meant fighting, which _ought_ to mean a pack of Jägers at their back. But the brothers had never quite trusted them, which was unfair - when they’d started their odd campaign, the towns they’d rescued had feared Heterodynes far more than Jägers, and many of those places were still expecting this to all be the setup to an elaborate madboy prank.
> 
> Lucrezia had, as usual, taken advantage of the brothers’ absence to fire another round in her ongoing covert war against the Jägerkin, but this time she’d gone too far.
> 
> It was strange, Jenka thought. Lucrezia ought to be far more to their taste than Bill or Barry - they were _good_ in a way Heterodynes had never been before, and Lucrezia had been the very model of a mad Spark before she had - or so the stories that had started popping up about the brothers’ exploits claimed - been Redeemed By Love. Certainly Bill was madly enough in love with her, and there were so few things the Jägers could do to make their odd ugly-duckling Heterodynes happy that they’d tolerate just about anything Lucrezia threw at them. But for all that Bill and Barry didn’t know what to do with them, they still understood that Jägers were not _things_. No Jäger doubted that if anything serious were to happen to them, the brothers would uphold the ancient contract and avenge them in a way that would make their ancestors proud.
> 
> And not one of them ever wanted to put Bill in the position of having to choose between them and Lucrezia.
> 
> But it was _hard_. Jenka hoped Bill would never realize just _how_ hard, even as she irrationally resented him for not noticing their restraint. The animosity between them went back to when Lucrezia had first been presented to the Castle. Jenka had watched as she’d looked dismissively past all her brothers - _just a bunch of big dumb soldier-constructs_ \- only to stop, startled, when she saw Jenka. The usual curiosity - _how? why?_ \- had flashed across her face, and then Lucrezia had pointedly looked away. _Yes,_ Jenka thought, _we’re people, not things, and you hate that I make you remember that._
> 
> Lucrezia had retaliated by giving her what she thought would be the worst possible jobs for a female Jäger - cleaning the lab, testing a ridiculous number of beauty products, and finally playing guard-nursemaid to baby Klaus Barry. That last had backfired; watching over the newest Heterodyne wasn’t a chore - quite the opposite; in previous generations such an honor would have been determined by combat - and it hadn’t taken Lucrezia long to notice. Jenka had been replaced by a construct whose fanatical devotion to the boy couldn’t be faulted even if her origins - and sanity - were somewhat in doubt.
> 
> All the Jägers adored their newest Heterodyne. Even if he grew up to be like his father instead of all his ancestors back to the first mad barbarian Sparks, he was _theirs_ , in a way Lucrezia obviously couldn’t understand.
> 
> Because now that the little boy was starting to walk and talk, she’d decided they were a “bad influence” and forbidden all access.
> 
> Jenka thumped the edge of the battlement in frustration. To her surprise, it suddenly extruded a stone manacle around her arm, pinning her to the wall. For one crazy moment she thought it was offended, which was not impossible but currently unlikely - she certainly couldn’t hurt it, and the Castle shared all her opinions about Lucrezia - when the tower shuddered and tilted, leaving her dangling over the castle walls and sheer cliffs leading down to the town, only the manacle saving her from a very painful drop.
> 
> An attack, then, and an incredibly stealthy one, if even the Castle had only had the barest fraction of a warning. She swung her free arm and legs against the wall, claws extending to dig into the stone. _And I really liked those boots_ , she thought irrelevantly, pulling herself awkwardly onto the top of the tower. She clawed at the stone holding her trapped and pulled as hard as she could, but it didn’t give. It felt dead, lacking whatever Sparky magic it was that let the Castle reshape itself. 
> 
> Down below, the initial shocked silence had given way to shouts and cries of pain. She screamed in rage and frustration and let the madness take her. When she pulled away again, the stone shattered to dust.

~.~

Bruce was just about to call the experiment off - he didn’t need the sensors’ confirmation to know that the locket wasn’t having any sort of dampening effect - when he heard a shout from the next room that set off sympathetic rumblings from the Other Guy. Jenka hadn’t expected any trouble when she’d volunteered to be his test subject - both Jägers seemed to take the entire process for granted - but she’d admitted she’d never tried to do it unprovoked. Bruce gave the monitors a quick glance, expecting the worst, but physically Jenka hadn’t changed since the last time he’d looked - still more fangs and longer claws than her baseline, but nothing compared to the Other Guy.

The look on her face, though… Whatever she was staring at, he’d lay odds it hadn’t existed since long before he was born.

Jarvis spoke up while he was still indecisive. “Shall I initiate the lockdown protocols, sir?” 

The Other Guy didn’t like that at all. For once, they were in agreement. “Not unless I start changing too,” he said, and opened the connecting door. Anyone who didn’t know about the sensors and reinforcements would think it was a perfectly ordinary meditation room. Tony had designed it for Bruce before he’d even extended the invitation to the Tower, on the assumption that Bruce could analyze his condition more easily in a room that didn’t make him feel like a lab rat.

As soon as he stepped in, Jenka visibly relaxed, her claws shrinking back to their normal state. The Other Guy seemed calmer as well, he noted. “Bruce?” she said, rubbing her arm as she looked at the monitor cuff now lying in tatters on the floor. “I’m sorry.”

“Don’t worry about it. I’ve been through more than a few of those myself,” he said, deliberately lightly. “I think we can confirm that the locket doesn’t do much to slow down the, ah, ‘madness place’ process.”

“I was just trying to remember how it felt, and then I couldn’t _stop_.”

He moved forward then, wanting to be comforting but still not convinced it would be welcome. She moved forward as he did and gave him a wan smile. Encouraged, he wrapped an arm around her shoulder. “You don’t have to talk about it if you don’t want to.”

“No… no. I want to.” She took a deep breath and began. “There isn’t even that much to tell. It was the day the Castle fell…”

~.~

There was absolutely no reason Tony shouldn’t be standing on the roof of Stark Tower. It was his tower - it still had one-fifth of his name on it - and his roof. He could let anyone he wanted set up a machine there, and it didn’t bother him at all that the exact spot which had once held a portal generator now held some strange Asgardian hybrid device to detect portals.

Not one bit.

“I’d have an easier time believing she was doing science if there was some Latin or Greek involved,” he grumbled to Thor. Jane didn’t even bother to look up.

“In truth, I do not understand it myself,” Thor said, “but Jane has a theory that the Convergence may have reopened the gateways to other worlds, and my father has offered our assistance in ensuring they remain closed.”

“Huh. I thought your dad wasn’t all that impressed with us lowly humans.”

Thor was silent for a moment. “When Jane visited our realm, she displayed an impressive understanding of seiðr for someone so untrained. It was my mother’s wish that she be allowed to return and learn more.”

Tony didn’t have an answer for that, so he just watched Jane while she finished doing - whatever it was. She looked up in satisfaction. “Done. There are higher levels of - um, I guess I could call it quantum entanglement resonance, although that’s not even close to being a good translation.” She grinned at them. “I was listening, you know. If you _really_ want me to be precise I’d have to show you the math. But basically there’s nothing here to worry about - this isn’t a natural weak point, that’s part of why it took the Tesseract to open it. And thanks again for letting me test it - there aren’t that many places where an artificial portal’s location is known so precisely.”

“Pleasure’s all mine. Really,” Tony said. Nice to know there wasn’t a potential hole directly above his tower that he couldn’t do anything about. “And I might even take you up on that math. But as for testing it, I think there’s something else you might be interested in.”

~.~

“Stop me when this sounds familiar. Secret lab, impenetrable fortress, surprise attack…”

“Not funny, Stark,” Jane snapped, looking like she was gearing up for a serious rant. From his vantage point in the back of the room, Clint silently cheered her on. If _that_ was what this meeting was about… But if so, why include the Jägers? He liked Maxim; he finally understood why the Heterodyne stories couldn’t decide if they were comic relief or unstoppable fighters. And Jenka reminded him of more than one protective older sibling from his foster home days. But he still wasn’t ready to share _that_ story with them. 

Bruce clarified. “What Tony is leaving out is that this was almost a hundred and fifty years ago.”

“Castle Heterodyne, right?” Clint asked, as all the pieces lined up. “Never did think that story made sense.” All eyes snapped to him. _And here I was trying to avoid attention_. “What? I grew up in a circus. Heterodyne stories still draw a crowd. All of that stuff from the old days - marks want to believe it’s a real Heterodyne device or a genuine Muse playing chess, not a kid crammed inside the box underneath.”

Thor frowned thoughtfully. “What tale is this?”

From the looks the Jägers were giving each other, Clint didn’t think they were any more fond of telling this story than he’d be. “Most of the stories I’ve heard,” he said, because nobody else looked like they were going to, “say that while the Heterodyne brothers were away, their enemies snuck in, destroyed the heart of the Castle, and kidnapped Lady Lucrezia from her lab. It didn’t make sense then, and even less now that I’ve met them.”

“Dey didn’t schneak in,” Maxim said. “Dey couldn’t have, der Kestle vould have squashed them like bugs. But if ve’d been dere, maybe…” He trailed off guiltily.

Oh, yeah, far too familiar. “You’re lucky you weren’t. Trust me,” Clint said, and Maxim must have read what he wasn’t saying because he didn’t even protest.

Jane spotted it then, and turned to Tony. “You think it’s a portal, like -” she gave Clint a quick apologetic look - “um, New Mexico.”

He took a deep breath. If Tony was right, the Jägers deserved to know - and probably would understand better than anyone else here. “Before they opened the portal here -” he waved vaguely upward, and took a small amount of satisfaction in seeing Tony flinch - “The scientist I was watching helped Loki open one right into the heart of one of our most secure bases and steal the device used to open the second one.”

The Jägers shared an appalled look. “She _wouldn’t_ have,” Jenka said, but she didn’t sound convinced.

Jane cut in. “Maybe not. Erik said he was under Loki’s influence even before that.”

“She _vas_ acting strangely,” Maxim said thoughtfully, then added, “More than usual.”

Jenka frowned. “But even though she did her best to get rid of _us_ , she couldn’t hide from the Castle.”

Clint frowned. The stories had treated the Castle like a character in its own right, but he still couldn’t quite believe it. “Yeah, all that stuff about it being intelligent -” He stopped, and mentally substituted _Stark_ for _Heterodyne_ in the stories. “OK, I’ve met Jarvis, I can maybe see that. But it didn’t _really_ move by itself, right?”

Thor looked at him, puzzled. “You do not craft your great castles such that they can reshape themselves to your will?”

There was a pause. “Er, no?” Tony said, speaking for everyone who wasn’t a Jäger.

“But a castle must see use for millennia; to cast it in anything but living stone would quickly render it useless. It is rare for lesser structures to be made thus, of course, but my brother -” He cut himself off with an apologetic look.

“Yeah, about him and the Tesseract,” Tony said, “There aren’t any more of those things around, are there?”

Thor gave Jane a look that seemed - guilty? apologetic? “There are, though I fear the knowledge of their location has been lost, and they would be a worthy prize for anyone with the skill to recover them.” He frowned thoughtfully. “But this could not have been my brother; the madness had not yet taken him. Though it would be foolish to assume he is the only one with knowledge of the ways between the worlds.”

“So if it was a portal,” Jane said to Tony, “you’re thinking it might’ve reopened during the Convergence. And if whoever came through last time was looking for something, they might be back.”

Clint thought about the stories of the Heterodyne Boys from after the castle’s attack. They weren’t so popular with the marks, who preferred the ones where the monsters were defeated. “SHIELD’s still mopping up stuff that came through then, so I think making sure of that is a _really_ good idea.”

~.~

Natasha and Steve shone their flashlights around the ice cave deep inside what had once been a HYDRA outpost, and before that the mountain hideaway of some long-forgotten Spark.

“Come on,” she said, carefully not noticing the way Steve tensed at the signs that something large had recently been dragged out of the ice. “Nothing to see here. Everything’s been cleared out.”

“Should’ve been cleared out decades ago, by _us_ ,” Steve said. 

She nodded agreement and let him precede her out the door. “Nearly everything would’ve been gone, even then,” she said. Most of the rooms they’d passed had been long empty, and all signs indicated an orderly evacuation. The ice cave would have been where they’d stored things too big - or too dangerous, in the case of a frozen Jäger - to be moved. “I’d say they meant to come back, though. Only… maybe a little sooner.”

Jarvis had narrowed down the search by correlating SI and SHIELD’s intel on the people behind Tony’s abduction and the Spark War-era artifacts - none Heterodyne, and nothing else as interesting as a Muse - that had been turning up on the black market. Steve had taken one look at the map and added another half-dozen locations to the list. All but one had been cleared by the Allies after the war; the last had never been found, presumed destroyed by an avalanche. 

But, Natasha reflected, that didn’t excuse them not digging for it at the time; someone should have had the intelligence to remember that any madboy who went to the trouble of carving a hidden lair out of the side of a mountain would have made sure the secret labs were well protected. Even from an avalanche that seemed to have buried it deeper than they must have expected.

Steve looked back over his shoulder. “So you agree this was HYDRA?”

She nodded. “It’s a working theory. Who else even knew where to look for the place? And they knew exactly where they were going when they got here.” The footprints and track marks had taken very few detours on the way to the ice cave.

She saw one of those detours up ahead. “We should check that out,” she said, waving her flashlight at it, and blinked. For a moment, she’d thought the wall there was solid. _Trick of the light_ , she thought, then looked a bit more closely. “Stop,” she said to Steve.

He’d spotted it too. “The footprints…” he said, and then grabbed a piece of rock and tossed it through the doorway.

It vanished, just like the footprints did. They shared a look. “Portals,” she said. Nothing but trouble. “Hang on, I’ve got an idea.” She snapped open a pocket, pulled out the burner phone she carried on missions, and tossed it through.

“Now let’s get back to Tony and find out where that went.”


	7. Chapter 7

“You want me to interrogate a _robot_?”

“Consider it a challenge,” Phil said dryly. “If you can’t do it, nobody can.”

Natasha cocked an eyebrow at him, knowing he’d read it as _Why is this so important?_

“We found your phone,” he said. “It didn’t go far. Didn’t even leave the planet. But we found other things too.”

“Giant spiders,” Darcy said, as they entered the briefing room where she was sitting cross-legged on the edge of the table, poking at the holo-display which, Natasha was not surprised to see, showed the town of Mechanicsburg. 

Jane batted her hand away absently, trying to zoom in on a section near the edge of the town. “And a stable, artificial, _terrestrial_ portal.”

“And giant spiders,” Darcy said. “Did I mention that? Because some people around here seem a bit unclear on the concept.”

Jane sighed. “Every time I find something interesting -” behind her, Darcy was making wiggly hand motions and mouthing the word ‘spiders!’ - “SHIELD comes along to take over.”

Phil just looked amused. “Actually this time we gave you first shot.” Natasha looked to him for clarification. “We’ve confirmed that the Muse did come from the portal you discovered. Dr Foster and her team sent probes in, and found, well - this.”

Darcy obligingly swept the display away, replacing it with a wireframe outline of a debris-strewn cavern. Dimly-lit video footage appeared on the display behind them. “And people said playing video games would never prepare me for a real job,” Darcy said, as the camera zoomed through a gap in the rubble blocking an arched doorway. Something moved in the distance, something about the size of large dogs, but dogs didn’t move like that. “See? Giant spiders.”

“I’ve seen a few of them on Asgard,” Jane said. “They aren’t _that_ dangerous.”

“Not helping!”

“What do the scanners show?” Natasha asked, ignoring the byplay. The Mechanicsburg valley had been under SHIELD protection since its founding days. The lookout posts on the mountain passes were quiet these days - the treasure-seekers having mostly given up - and could’ve been completely automated, but SHIELD found it useful as a rest/reward posting for agents with a preference for skiing over beaches.

“That’s the problem,” Phil said. “They don’t. None of that is on our maps.”

Darcy brought the holo-display back up. There was a tracery of wireframe tunnels under the city, but the bright dot she zoomed in on wasn’t near any of them. 

“She was waiting by the portal,” Jane said. “She knew it was there, so if there are others she might know about them too but nobody will let me _talk_ to her. Somebody was making stable artifical portals over a century ago with clockwork tech and I don’t even know how to do that _now_. And this could be my only chance to study them, because the convergence -”

“Lit up all the portals like closet doors in a Monsters Inc factory,” Darcy sing-songed in the tone of someone who’d had to deflect the technical explanation too many times already. “But they won’t stay open forever, which _some_ of us -” she made the wiggly finger-gesture again - “have no problems with.”

Natasha shared a look with Phil. _And some of us would like to find and close those portals now._

~.~

Tinka sat, unmoving, in one of the rooms SHIELD set aside for people whose guest status could be revoked at any time. Natasha knew from the reports that this was normal. _Not as if it - she - could sleep._ She rose to her feet gracefully as Phil and Natasha entered the room. Someone had found her a dress to replace the one that had been damaged at the museum, a classic style suitable for a dancer. Natasha wore something similar; in a normal interview it would be a subtle indication that she was a potential ally. _Get the target to identify with you._ Right. Now if only she knew how to work that in reverse.

“I’ve met you before,” Tinka said to Phil, her body language and even her face - far more expressive than Natasha had guessed - registering as pleased to see him.

“At the museum, yes,” Phil said. “Phil Coulson, Strategic Homeland Intervention Enforcement and Logistics Division. Which probably doesn’t mean anything to you, but one of our tasks is to watch out for Spark devices like you and keep them safe.”

She tipped her head down and smiled up at him. “I feel safer already.”

Phil gave her the smile he reserved for interrogation subjects he needed to charm. “And Natasha Romanoff. We have some questions about the museum and how you came to be there.”

“Oh…” Tinka said, and frowned. “I don’t really know anything. The first thing I remember is that clank saying he came from the Storm King, but I knew that couldn’t be true -” her voice caught - “because I saw him die when the Castle went mad.”

 

They’d worked together enough that they slipped easily into the roles Tinka seemed to be expecting - Phil the protector, Natasha curious and awe-struck. It was familiar - too familiar, Natasha thought. Her instincts were no use; they said _she’s trying to play him_. She’d done the same to more marks than she could count; making yourself seem like someone who needed protecting was a classic because it worked. But something about that struck her as wrong.

She’d once watched an amateur smuggler get caught. The woman had dressed as a nun in full habit, but she’d been nervous instead of confident, last off the plane instead of taking advantage of the unconscious tendency of her fellow passengers to clear a way for her. She hadn’t made it past the Customs inspectors. Natasha didn’t even remember what mask she’d been wearing at the time. It didn’t matter; she had sailed through, unnoticed.

_Something as rare and valuable as a Muse ought to expect respect and deference as a matter of course. This one doesn’t._

If it weren’t for the physical evidence, she’d swear she was dealing with an agent who’d picked a cover role they didn’t know how to play.

_If she told me there was a trap up ahead, I’d make sure she went in first._

Which was the problem, because the one thing she said that Natasha found believable was that there was more to the Castle than SHIELD knew, that it was full of traps, many of which might still be working, and that learning everything Tinka knew about them would take more time than they had.

What she needed was an expert on the Castle, and even, if possible, the Muses, and she knew exactly where to find one.

~.~

Natasha tracked Jenka down to Tony’s library, where she was curled up catlike in one of the comfortable chairs and - knitting? _This day is not permitted to get any stranger._

“I need your help,” Natasha said. “I’ve been talking to the Muse-” She trailed off, not sure if she was being ignored, and wondered if going to someone _else_ she wasn’t sure she could read was such a good idea after all.

Jenka glanced up briefly at that point - Natasha would swear that wasn’t a coincidence - then continued to the end of the row and put the knitting aside. “About the Castle?” she prompted. “What did she say?”

_Focus. Don’t let her get to you._ “Nothing we didn’t already know, but it’s the details -” and yes, she knew that was what Jenka was most interested in, but that was the problem. “I don’t know how much to trust what she says. She’s a clank - a _machine_. I’ve never had to deal with one, not like this.” The awe-struck scientists at SHIELD couldn’t stop babbling about how there’d _never_ been one like this. “But I thought you might.” 

“Really? I’m not sure how I could help. We never fought them, you know,” Jenka said, just a little too ingenuously, and Natasha had to remind herself to stop underestimating her. Turning serious, she said, “I’m not sure… I only saw them once, on a state visit to the Storm King.” She looked away, reminiscing, while Natasha tried to imagine a court scene that included both Jägers and Muses. “They were very… distant. Even when they weren’t on a pedestal, you thought they ought to be. But gracious, even to us.”

Natasha frowned. “That’s what I expected, but I’m getting…” She trailed off, frustrated - an unfamiliar feeling. “I don’t know. I can’t tell if I’m reading her right.”

Jenka shifted slightly. The move wasn’t an obvious threat - if anything, she looked more relaxed - but Natasha was suddenly acutely aware of where all her weapons were and how long it would take to reach them. _Too long._ Natasha didn’t move, didn’t give any indication that Jenka was setting off all the same alarms Maxim did ( _and Bruce, but don’t think about Bruce_ ).

“You don’t trust me,” Jenka said, and gave her an approving grin that wasn’t at all reassuring. “Smart girl. _Trust_ your instincts.” She paused for a moment to let her point sink in, then made a show of settling back into her seat. 

Natasha didn’t relax, even though Jenka seemed much more - human? No. Now that she knew what to look for, she could see how much of it was an act. _That’s what I was missing,_ she thought. They were both creations of mad science who’d survived when the others like them hadn’t. Jenka had disappeared into the crowds, pulling humanity back on like a mask, and Tinka - well. She was here, so whatever she’d done had worked. _She may be putting on an act, but it’s an act I know how to read._

She took a deep breath, settling herself. “My instincts say… she’s not telling all of the truth. She wants something and thinks she can manipulate us. Phil, mostly,” she added wryly. “Not sure I even registered.” And Phil was letting her believe it was working; she couldn’t be as good as she thought she was if she hadn’t seen through that. Or noticed that Natasha was the real threat. She gave a slight smile at the realization - this _was_ her sort of game after all.

“Tell me what she said, and what you think are lies. I’ll tell you what I know.”

“I can do better than that. Jarvis? I know you’ve got eyes in there.”

~.~

Sometimes Jenka envied Maxim. He’d never had to learn how to blend in with the potential angry mob - to be fair, because he’d been the next best thing to killed by one - and then fallen in with a group that felt more like _home_ and _pack_ than anything since the Heterodynes had vanished. He wasn’t unaware that Natasha saw them all as dangerous monsters - she was very, very good at hiding it, but Jägers could scent fear - but the days when that was something they expected and encouraged, even from their allies, were still far too recent for him.

Which was why Jenka had been surprised when Natasha had asked for her help. 

“She’s sticking to the story they told when they went in,” Natasha said, as they headed for the nearest room with display capabilities - there was nothing Sparky allowed inside the library except Jarvis, who was family by Jenka’s reckoning and didn’t count. “That Zola was the Heterodyne heir, raised in secret by her aunt -”

“Not a chance,” Jenka cut in sharply, forgetting for the moment that she was trying to be less threatening. “She might have been Lucrezia’s but she was _never_ Bill’s. When you’ve fought alongside more members of the family than you can count, you _know_.”

“Our researchers are convinced she really was Lucrezia’s niece,” Natasha said. “They’re not so sure about her companion. Tarvek of Sturmhalten, heir to the Lightning Throne, or so he claimed.”

Jenka shrugged. “He could’ve been. I don’t think anyone outside that family could keep them all straight. He looked enough like old Andronicus.” They’d both had the same distinctive red hair as Natasha, but if she didn’t know about the resemblance Jenka wasn’t going to say anything. It wasn’t as if it mattered; they were all long dead.

“Tinka says - well, you should see for yourself. Jarvis?”

As Natasha had said, she hadn’t departed from the original story, carefully crafted to match the supposed prophecy of a Heterodyne Princess and a Storm King united to bring peace to an unstable empire. Jenka knew better. They were both agents - or pawns, depending on who she’d asked - of the Valois family conspiracy that had set off the instability in the first place. They’d meant to use the chaos to take over the Castle, but their attempt had prompted imitators, minor rebellions had become major, and the Castle had chosen to go down fighting, taking all its enemies with it. 

In Tinka’s version the Castle had been more mad than they’d thought; unwilling to accept the prophecy, it had taken Tarvek out without any warning. “That’s only partly the truth,” Natasha said. “I believe it killed him. I just can’t tell what she’s leaving out.”

Jenka took a few moments to collect herself, pushing the accent as deep as she could; she’d frightened Natasha enough for one day. _So close_. After so long she’d finally learned which of them was to blame, but she still didn’t know how the Castle had died. “The only thing that surprises me is that _she_ wasn’t the first to die. The Castle was tolerant of the Sparks that were sent in to repair it, but a fake Heterodyne trying to take control should’ve been squashed like a bug.” She paused, searching her memories. “There were stories at the time that she could make the Castle listen to her, and some of the survivors claimed they knew someone who’d made a device that could control it. But that was the sort of thing they’d want to believe.” The repair crews had been prisoners, not volunteers. The Castle’s mind had been fragmented; the places most need of repair were also the most carefully protected, so it wasn’t uncommon to have the Castle unknowingly send a crew into one of its own traps.

Natasha and the other SHIELD agent hadn’t been as interested in the past as Jenka was; they’d steered the conversation more towards Tinka’s escape. She’d claimed that Zola had sent her away once things looked hopeless, that she’d made her way alone to a dead end where she’d expected an exit. “Which strongly indicates that she knew about the reports their inside man smuggled out, and probably the portal as well,” Natasha said, and Jenka had to agree. “What we need to know now is whether we could make it through the Castle without her.”

“I wouldn’t try it,” Jenka said. “When we lived there the Castle’s traps were a game - it always gave us a sporting chance of surviving them.” Natasha gave her a look that was very clearly _your idea of fun and mine are very different_. But she was amused, not frightened. Progress. “The Castle spent over twenty years insane and paranoid, and it took all that time for the people inside to make any sense of it. We’re tough, but we aren’t stupid - if we have to go up against what the Castle left behind, we’ll take any advantage we can get.”


	8. Chapter 8

Darcy skiied to a stop beside the SHIELD agent and paused to admire the view. _And the scenery’s pretty nice too_ , she thought. Which, yes, was shallow - she’d totally admit it. But Agent Higgs looked like someone had taken Thor and scaled him down to merely human proportions. _Like a fun-size version. And we could use a bit more fun around here_. There was only so much time she could spend watching Jane and Bruce watch the equipment before she went stir crazy.

There’d been a carefully marked trail through the forest but Higgs had taken her along another route. “There’s another cave entrance here,” he said, pointing to a barely-visible crack in the side of the mountain. “But don’t go in this one alone unless you have no choice. You could lose a small army in there, if you know the markings well enough not to get lost yourself.”

Darcy suspected in the old days they’d done exactly that. She could picture it - an army of mad Sparks and constructs, chasing each other through a maze of twisty passages. “You get a lot of small armies up here?”

“Not these days. Mostly desperate Latverian refugees.”

“Uh-huh,” Darcy said, looking up at the mountains. “ _Very_ desperate ones.” There were no passes on the Latverian side. Not that many on the others, either. “You know, Thor said this place was very defensible, but I’m thinking that just makes it harder to get out when things go wrong.”

Higgs smiled. “He’s right. We’re pretty safe up here.”

“Yeah, but down there? Giant spiders and ghosty-ladies and who knows what else?”

“Geisterdamen,” Higgs corrected. “They used to tell stories around here about them, the wandering ghosts who can’t rest until their search is over.”

“Really?” Darcy perked up. Maybe she wouldn’t be totally useless up here after all. “Thor says they come from one of his worlds. He doesn’t know why they’d be here. Sure got everyone worried, though. Do the stories say what they’re looking for?”

Higgs shrugged. “You know how ghost stories work - anything from a hidden treasure to the lost Heterodyne heir.”

Darcy nodded as they started to ski off again, but Higgs stopped her when she began to pull ahead. “If you take the obvious route over that hill and miss the curve, I’ll be digging you out of a snowbank."

Darcy followed him carefully to the top of the hill, peeked over, and shivered. Snowbank, right. And a cliff beyond that. She paid close attention as Higgs pointed out the landmarks she’d need to aim for to find the safe route down. “You know, I can’t help but notice that you’ve been giving me the grand tour of traps and escape routes here,” she said. “I mean, normally when a cute guy invites me out skiing, it’s because there’s a nice hot tub waiting at the end.”

“Well, you looked like you needed a distraction,” he said, giving her a smile that said yes, hot tubs could be happening in the future. This had been the Heterodyne’s ski lodge, after all - it had all the amenities as well as the traps. “And I suspect you’re the sort of person who likes to know where all the escape routes are.”

“Oh, yeah,” Darcy agreed, following in Higgs’ tracks as he skied carefully around what looked like an ordinary section of the trail. “I just love pointing them out as we run right past them. But that’s Sparks for you. Ever worked with them?”

“Once or twice, yes,” Higgs said, looking over his shoulder at her with the long-suffering look of someone who knew exactly what she meant.

“Then you know. Show them something dangerous that you absolutely ought to stay away from and the next thing you know you’re taking out a Norse god with a taser or falling through a portal to another world. Or _hunting_ for one, which is even crazier.” Though 

They’d stopped on a ridge that looked out over the town. Higgs didn’t point out any traps or potential ambush sites, so she took a moment to relax and just appreciate the view. The valley floor was dotted with overgrown wreckage of the airships and battle clanks from the final battle. The castle itself was a picturesque ruin, though judging by the reports that had come in from Tony’s team, what everyone had thought was the castle was only the tip of the iceberg.

“Worried?” Higgs asked.

She shrugged unconvincingly. “Why should I be? I’m up here, the dangerous stuff is down there, and the only way in we know about is 50 miles…” she waved vaguely northward, “that way.”

“So you’re expecting trouble.”

“Damn right.”

~.~

“This is it,” Tinka said. “Lady Lucrezia’s laboratory.”

There was a time when Maxim wouldn’t have needed to be told where he was. He would have simply known, even when the Castle was at its most mischievous. He looked around for something familiar, but there was nothing - no equipment, not even a trace of the damage he remembered, just the same markings and graffiti that Tinka had used to navigate the Castle.

He still wasn’t pleased that an outsider knew more about the Castle than any of them, but he had to admit that they wouldn’t have gotten this far without her - the Castle he remembered had been dangerous, of course, but only if you weren’t careful. This Castle… he rubbed the nearly-healed cut he’d gotten from a trap that would’ve been fatal if it had been in better repair. Even in the worst sieges, the Castle hadn’t been so indiscriminate with its traps.

The shadows shifted as Tony’s floating clank-bot took its position near the ceiling, spreading light and scanning the surroundings. Tony had his visor down, checking what it had found. “Still no sign of any portals,” he said, flipping up the visor. “But I’m picking up some sort of power signature…” He pointed off to the left. “That way.”

 

Tony led them down the corridor to an archway that appeared to have been bricked over. At eye level on the wall, deeply embossed in what Maxim recognized as the Castle’s handiwork, were the words “You will need this” in the old Mechanicsburg dialect. Beneath it was a trilobite sigil and an open-mouthed gargoyle face.

Tinka shifted uneasily. “According to the records, this should be a blank wall.”

“All the more reason to check it out,” Tony said, bending down to take a closer look. “If this is a door, there should be some way to open it.”

“Bloodlock,” Maxim said, pointing at the gargoyle. “Only a Heterodyne can unlock it.”

Tony looked at it skeptically. “Biometrics, here?” he muttered, but the gauntlet was already sliding back. He raised his hand and placed a finger in the gargoyle’s mouth. “Ouch!” He pulled his finger out and shook it, glaring at Maxim. “Not funny,” he said, and Maxim only then realized he was grinning - _this_ was the Castle he remembered. Whatever it had hidden from the Geisters and the Baron was going to be _good_.

~.~

Tarvek didn’t expect to be alive.

Between one blink and the next he found himself stumbling into a crowd of people. Someone caught him, metal arms holding him close - only a lifetime of practice kept him from pushing her away - with an enthusiastic “My king! You’re alive!” and a much softer “Remember the plan.” The _or else_ came through loud and clear.

_As if I could forget_.

Out of the corner of his eye he caught a flash of familiar red. _So the Smoke Knights came through after all._ While Tinka was still wrapped around him he signaled _danger_ and _say nothing_. She looked startled, but signed back confirmation.

Tarvek stepped back, adjusted his glasses, and took a good look at Tinka and her companions. Between the time the Castle had grabbed him and then thrown him back out Tinka had somehow found herself a more practical outfit - he’d felt the stiffness that indicated some kind of impossibly thin armor - in a similar style to the redheaded woman and a tall blond man. Uniforms, possibly, which couldn’t mean anything good. Just past them was a man in an armored suit, one bare hand still raised to the wall beside them. And beyond him…

_Jägers._ Tarvek reconsidered whether he was actually lucky to be alive. Maybe the Castle had just thought that if it squashed him it would be over too quickly. “But… you aren’t allowed in the town,” he blurted, and then wanted to kick himself. Baron Wolfenbach had sworn to protect the town until the Heterodynes returned; in exchange, the Jägers would serve under his command - effectively separating the town from its army. Zola’s role in the plan had depended on that; his father and the rest of the Order had thought it highly ironic to use the Baron’s precautions against him. The uprisings they’d set off throughout the rest of the Empire were meant to serve the dual purpose of distracting the Baron and eliminating the Jägers while they consolidated their hold on the Castle. 

Tarvek personally thought that assuming the Jägers would lose was the weakest part of an already unstable plan; they weren’t stupid, no matter what the stories said, and serving the Baron instead of the Heterodynes didn’t make them any less dangerous. And it would be just like a Wulfenbach to have contingencies for situations exactly like this. He couldn’t send Jägers against the town, even if someone else held it, but it had been foolish to believe that he’d never send them _in_.

Tarvek considered it said a lot about the way his life was going lately that reminding the Jägers of his part in the whole mess was only the _second_ stupidest thing he’d done today.

“Hyu may not haff noticed,” the purple one said, glaring at him, “but dere izn’t any town.”

“No town?” That hadn’t figured in _any_ of his worst-case scenarios. How badly had everything gone off the rails? _How long had it been?_

“Ah, could someone translate here?” the armored man said in English, “And maybe ask him if he knows why the Castle seems to think we’ll need him?” He tapped the wall beside him. Tarvek turned to read the inscription and seriously considered banging his head against the wall; it couldn’t make the day any worse.

“Because the Castle thinks it has a sense of humor,” Tarvek answered in the same language. “I said I wanted to help it.”

“Yeah,” the other man said, with a quick glance down at his hand, “I’ve noticed. But that’s not the story I heard.” There was a hint of possessive madboy harmonics lacing the man’s words. _She’s found herself another Spark. Of course._

Tarvek shrugged and spread his hands out in supplication. He shot a look at Tinka; the others should hopefully read it as _help me convince them_ but she’d know better. _You want me to play along, I’m going to need some help._ Never one to miss a cue, she said, “We saw the Castle take you away - we thought you were dead.”

_That’s the game, then._ He could work with that.

The armored Spark frowned. “That makes you Tarvek, then? Tony Stark.” He nodded at the rest of them. “Tinka you know. Jenka, Maxim, Natasha, Steve.” He shook his head. “I wish I _could_ fix the Castle, just so I could ask it what the hell it thought it was doing.”

Fix it? Come to think of it, the Castle _had_ been suspiciously quiet. “Could someone just tell me _what’s going on?_ ” Tarvek asked.

Tony looked at Steve like he expected him to have the answer. Steve opened his mouth to speak and then stopped, giving Tony an unreadable look in return.

“Idiots.” Natasha pushed between the two of them with a look of fond exasperation that was so familiar it hurt. He closed his eyes and leaned back against the wall, almost wishing the Castle would swallow him up again. _Violetta_. She was - she’d _been_ out there. He’d seen her in the crowd on their ‘triumphal’ entrance into the town. If he’d given her the signal she’d have followed him in, but he’d wanted her to stay _safe_ …

“Listen to me.” He felt hands on his shoulders and opened his eyes to see Natasha looking intently at him. “Yes, the Castle is dead. It’s still dangerous. Whatever part of it that protected you is gone. This is now a very bad place to have a breakdown. All those questions you have? _Don’t think about them._ Not until we’re safe. Can you do that?”

He took a deep breath. “Yes.” He was _good_ at that. “But, just one question first… the town - the people. What happened?”

He was so focussed on Natasha that he hadn’t noticed that Jenka had moved next to them until she spoke. “They got out, but vitout der Kestle’s protection…” She paused, watching him carefully, and Tarvek realized she was avoiding anything that might invite the questions he wasn’t going to ask, “the town vas abandoned.”

“And Zola?” He looked at Tinka, who shook her head sadly. “Then… if everything’s gone, why are you here?”

“The Geisterdamen have found a way into the Castle,” Tinka said.

“Oh?” He frowned, still trying to adjust his thinking around the fact that it wasn’t still the same day. “Oh! Of course. If the Castle’s really dead it can’t stop them anymore.”

That got everyone’s attention. “What do you know about them?” Tony snapped.

Jenka snarled an answer, with a glare directed at Tarvek, “There vere stories that his family worked vit dem,” which Tarvek found oddly reassuring - threats he could deal with, but sympathy from a Jäger was far too unsettling. 

He rolled his eyes. “Yes, but if you know _anything_ about my family, you know how much that’s worth. They’ll use them only as long as they think it’s to their advantage.”

“The Geisters were looking for something.” How much should he reveal? If anything was left of the conspiracy it only had one hold left on him, assuming they’d even kept that promise; recent events had shown just how expendable a pawn he’d really been. These people weren’t allies, but he found himself oddly sympathetic to anyone who wasn’t on his family’s side. “I was never told, but if I had to guess, it’s something to do with the Castle’s power source.” He’d worked out where he was, now - he’d memorized all the reports, and this doorway wasn’t on them. There could be only reason the Castle had kept it hidden until now. He nodded at the stairs spiralling down behind him. “Somewhere down there.”


	9. Chapter 9

Natasha’s first impression of the cavern deep underneath the Castle was that it was exactly what she expected from a mad Spark’s lab. 

She said as much to Steve while they were waiting for Tony to finish his initial scans. Steve took a good look around and nodded. “Not sure what’s more disturbing, the restraints or the cages,” he said dryly.

“Tough choice,” she agreed. “Sit down around here, you might never get up again.” Even more disturbing was that it all looked strong enough to hold a Jäger - she looked at the two of them uncomfortably. This _was_ the Heterodyne’s Castle, after all - maybe this was all normal to them?

“Dis vas Lucrezia’s,” Maxim said, looking with particular distaste at something that looked like a cross between a mechanical octopus and a helmet. “Hy recognize her style.”

“This is where the attackers came through?” Steve asked doubtfully. Unlike the rest of the Castle, it was obvious nobody had ever been here to repair the initial damage; tables were overturned and fallen rocks were everywhere. The rest of it… didn’t really invite closer examination.

Jenka shook her head. “That was up above, the one we knew about. This part of the Castle…” She trailed off, looking up at the ceiling as if expecting to find an answer written there, then shot a cautious look at Tony.

_Ah. So this is where the Castle kept its most important secrets._ She glanced over at Tarvek. _So where does he fit in?_ “I’d like to talk to him without _her_ around.” Tinka had attached herself to him and brought him up to date, at least as far as her part in the recent adventures were concerned, keeping him away from everyone else as smoothly as Natasha herself could have done. Other than that first signal, he hadn’t paid any more attention to her than anyone else, though she didn’t doubt he was as curious about her as she was about him. She still wasn’t sure what that code was or how she’d known it. 

“Yah, so would I,” Jenka growled, giving the pair a thoughtful look. “Hy could distract the clockwork girl for you.”

Natasha considered it. “Maybe later. I can still learn things from watching them together.”

~.~

“All clear,” Tony said. “No power sources, no portals. If I were you I wouldn’t touch anything that looks like it has moving parts, but there’s nothing obviously dangerous.” Or obviously interesting, either. “Jarvis, let’s lose the suit.” The Jägers shared a look and then took up positions at the door. Tony had left a trail of sensors behind them, so Jarvis would warn him if anything happened.

“So.” He raised a questioning eyebrow at Tarvek. “Anything here look interesting?”

Tarvek took a few steps into the room, looking at the various devices while keeping a respectful distance. Tony trailed after, wondering why he found it all so disappointing. It was, after all, the first functioning Heterodyne lab they’d found, untouched since the days when his ancestors had still been in residence; there had to be something here worth all the trouble.

Tarvek stopped and shook his head. “Nothing - no, wait, what’s over there?”

The scanner ’bot obediently floated over to light up the deeper recess of the cave. Tony’s first thought was that there was a body chained to the wall, but a glint of light revealed metalwork. _Clank, then._ Looked like a mechanical angel. Tony wondered if the wings had been functional - could they have made light enough alloys when it had been built? 

Tarvek was moving forward as if transfixed. “Otilia,” he breathed. “Muse of Protection. She’s been lost for over two hundred years!”

_Another Muse? What were the odds?_ And what was she doing here, of all places?

“I don’t think the Castle saved you just so you could restore my sister,” Tinka said, which struck Tony as an odd thing for her to say, even though it was pretty much what he was thinking. Before he could comment, Otilia jerked forward as far as the chains would allow. Tarvek, startled, leaped just out of reach. Tinka shrieked and hid behind him, clutching his shoulders.

“Where is she?” the winged Muse shouted, looking around the room wildly. “I know that voice. Lucrezia, you coward, show yourself!”

Tarvek looked over his shoulder with a look that seemed almost guilty. “Lucrezia isn’t here. What you heard - it’s her voice, yes.” He winced as Tinka grabbed him more tightly. “But she only _sounds_ like Lucrezia. I should know, I made her.”

Otilia stared down at him, then at the cowering Muse behind him. “You gave her voice to _that?_ ”

Tarvek stared back. “I had no choice. But she may be the only one left who’ll tell me where the real Tinka and Moxana are, so I want her alive. I am Tarvek Sturmarous, heir to the Lightning Throne. I am your Storm King. They have sworn their allegiance to me, and I demand you do the same.” 

Otilia drew herself up regally, wings flared as much as her position allowed. “You think I am one of your pretty toys? Even in this pathetic form I am Castle Heterodyne!”

Tony glanced over at the Jägers and mouthed “Castle?” They shared a look and shrugged. 

Tinka shrieked. “Tarvek, protect me! You have no idea how much it hates me!”

“I can guess,” Tarvek muttered, looking over his shoulder at her disdainfully. In a voice laden with Sparky harmonics, he said, “Zola, _freeze_.”

“Tarvek, what—” she started. He shrugged his way out of her grip as she stood there unmoving. Panic in her voice, she continued, “What have you _done_?”

“Never seen that work before,” Tony said admiringly.

“Helps to put the kill switch in _first_ ,” Tarvek said, with a quick glance at Tony that was practically smug. It vanished as he turned back to the chained Muse. Behind him, Tinka - Zola? - was getting increasingly desperate.

“You have no idea what you’ve done! Tarvek, _please_ -” Her voice cut off, and when she spoke again it was in a low seductive tone that in Tony’s experience inevitably meant trouble. “You really, really don’t.” 

“Lucrezia?” Tarvek spun around and stared. “You shouldn’t be in there. She said you weren’t!” 

“And if you’d known,” the Muse - whoever she was - purred, “you’d have wiped us and tried again. Besides, until you _ever_ so kindly shut her down, she’d still have been able to control me. But now?” She stretched her arms out as if getting the feel of them, and Tarvek went pale. _Only one kill switch? Oops._ The winged Muse pulled desperately at her chains. “Now I’m back. Just one little problem left to dispose of…”

Blue sparks began to crackle over her body. Tony summoned the suit’s gloves, though he knew it was already too late.

Tarvek grabbed her. For a moment they were both outlined in blue fire, and then Tarvek shot one arm out with a blinding flash. When the spots cleared from Tony’s eyes Tarvek was on his knees, head down with one hand clutched to his chest. _Not good. Really not good. But at least he’s still breathing…_

“Take it from me, Prince Zuko,” he said, “Running electricity anywhere near your heart? Not a good idea.”

Tarvek looked up with a mad grin. “It _worked!_ ” He pulled the scorched remains of his frock coat away, reveaing some sort of harness covered in wiring. “I wasn’t sure I had the insulation right. I couldn’t exactly test it, or she’d _know_ , and -”

“Ever consider not giving her lighting powers in the first place?” Steve said, cutting him off in a tone he’d directed at Tony far too many times.

Tarvek glared as he staggered to his feet. “I made that body for my _sister_ ,” he grumbled. “Anyway, it was part of the original design. It’s how they recharge - and protect themselves.” He winced and looked around. “Where’d she go?”

Tony looked around, but there was no sign of her, and the Jägers only shruggged.

“This was her lair. You think she didn’t have an escape route?” the Castle-Muse snarled. 

Tarvek gave the Castle a wary look. “She’s going to run straight for the Geisters.”

“They’re here?” the Castle asked. Tarvek nodded. “She must be _stopped._ And you - you brought her here! _You will die!_ ”

“Enough!” Tony snapped. “Someone explain what’s going on. Now.”

Tarvek looked between Tony and the Castle, obviously considering what to say, and then gave a resigned shrug. “Of course, you wouldn’t know. Lucrezia wasn’t kidnapped when the Castle was attacked. She let them in.”

“This is sounding terribly familiar,” Natasha said softly behind him, and Tony had to agree. 

“With the help of _your family_ ,” the Castle snarled.

“I was a _child_ when that happened,” Tarvek snapped back. “And this? It _wasn’t my plan_. Zola was the one who wanted you destroyed - and _me_. We have a common enemy, even _before_ we get to my family.”

Right. Time enough to sort that out later. Lucrezia-Tinka-Zola-whoever had just tried to destroy the last working part of _his_ Castle’s AI, and Tony was taking that very personally. Even if he wasn’t terribly impressed with the Castle’s approach to talent acquisition.

“Look, you’re obviously an out-of-date backup copy so I’ll forgive you this once. The original you sent him down here, obviously to repair you. So even if he weren’t under my protection - which he _is_ \- you don’t want to harm him.”

The Castle glared at him. Tony stared back, unimpressed. “And who are you to dictate what I do?”

Tony smirked. Opportunities like this didn’t come along often and he was going to enjoy it. “I am Tony Stark, last descendant of Bill and Lucrezia Heterodyne, and - you know, I’ve always wanted to say this - you were created to serve me.”

“Prove it.”

“I have Jägers.”

The Castle twisted, trying to see the doorway. “Show yourselves!”

Maxim stepped forward. “Iz true,” he said, and then continued in a language that had even Natasha and Tarvek looking baffled. After a brief conversation, Maxim said, “Hy don’t know how, but dis iz der Kestle.”

The Castle nodded. “Yes. And since they accept you, it seems I must also. Now, cut me down.”

“Promise not to hurt him.” 

The Castle considered Tarvek for a moment. “You put Lucrezia’s mind in that body?”

Tarvek grimaced. “I put _Zola’s_ mind in that body. Lucrezia was just a stowaway.”

“Yes,” the Castle said thoughtfully. “She _would_ do that.” She turned back to Tony. “I am no copy. I am a fragment. She cut me off from the rest of myself and then placed me in this insufficient shell. If he can reverse that, I will let him live.”

Tony thought about that for a moment. The Castle seemed - well, about as homicidal as the stories said, but then the same was true about the Jägers. But right now there was only so much it could do. “All right, let me just -” Before Tony could take aim at the chains, the ground began to shake. “Oh, now what?”

Tarvek stumbled and Natasha appeared out of nowhere to catch him, Steve just a moment behind, shield raised over them all. Tony summoned the rest of the suit which snapped around him just as the part of the ceiling that had been hit by Tarvek’s lightning strike cracked open, spilling rocks and machinery across the far side of the room. 

The HUD lit up as the faceplate snapped down, half the sensor readouts flashing red. “Oh, this is not good.” He hadn’t seen anything like that since they’d been hunting the Tesseract.

The Castle was looking up at the crack in the ceiling like a flower turning towards the sun. The gold inlays glowed, and this time when she pulled against the chains, they snapped.

“Ah,” said the Castle. “I’m _free_.” 

“That’s your power supply,” Tony said. This had to be what the Geisters were after - if word got out, _everyone_ would be after it. “Right. This I’ve got to see.” 

Ignoring the protests from Steve and Natasha, he flew up through the hole in the ceiling into a vast cavern that dwarfed the one he’d left behind. He was so used to the blue glow of the arc reactor that it took him a moment to realize that the light here was coming from the river, not reflected by it. The light was brightest in a small pool that seemed to be the source of the river. The floor was covered with ancient machinery in various states of disrepair, and Tony itched to take it all apart. “The power readings are incredible. But the size of these devices…” He could see what they’d been trying to do, but the technology just hadn’t been up to it. “I could do _so much better._ From here, I could do _anything_ …”

“This is the Dyne,” the Castle said, climbing up the rubble from the cavern below. “This is what powered _me_ , and this is where your ancestors learned to harness it.”

Tony sobered up abruptly. His _mad scientist_ ancestors. And if it was related to the Tesseract, it had to be kept out of the wrong hands. “At least Lucrezia was already gone when this happened. She doesn’t know this is here.”

The Castle shook her head. “Why do you think her lair was so close? She has always known it had to be near, but so long as the rest of me was intact, it was protected. Now… she will return to her lab with an army, and she will find _this_. You _must_ restore me to my rightful place before that happens.”


	10. Chapter 10

_They have a Heterodyne. And he’s older than I am._ Natasha was right, Tarvek mused; thinking about all the implications of that wasn’t going to lead anywhere good. But it would be useful to know the current state of family politics. Just as he decided to ask her, he found himself faced with both the Jägers.

“So, Lucrezia let them in,” Jenka said bitterly. “ _She_ vas der Other.”

_The Other_. Tarvek almost laughed. Of all the things to ask, she’d started with that? “Yes,” he said, and then - _why not, what does it matter now?_ \- “And also the Gesterdamen’s Eternal Goddess. She controled the revenants. She used the slaver wasps to turn your allies against you.”

They shared a look of grim acceptance. It was news to them, then, but not surprising. And if it had been? Part of him knew that telling Jägers just what his family had planned for their Heterodyne was a potentially fatal idea, but he was floating on something very like the madness place too much to care.

Steve looked up from where he was standing guard by the rubble and frowned thoughtfully. “Slaver wasps? As in the hive engines?” Tarvek nodded. “There were rumors that Hydra had found one during the war,” he said, and Tarvek wasn’t going to ask, “but they couldn’t make it work.”

“Without her to activate it, the majority of the infected act normally. Her voice alone can control the weak willed - the voice, with her behind it? They can’t resist. At _all_.” His father had insisted on testing it.

“But vy?” Maxim asked. Tarvek only shrugged. Power, of course, and minions that had no choice but to obey. What else did any mad Spark ever want? He’d been tempted himself, until he’d seen what it actually did. Even if they’d only been peasants, they’d been _his_ townsfolk. And there was always that _special_ engine… “Und how did she end up as a clockverk gurl?”

“Lucrezia had a daughter -” They didn’t look surprised. _Right,_ he thought, eyes flicking up involuntarily to the hole in the ceiling. _Of course they know that._ “She was meant to be the perfect vessel for the Other. The Eternal Lady. And then they lost her. My family, the Geisters, they all looked for her, and she _escaped_.” Lucky girl. _He’d_ never found a way to manage it.

“Zola was Lucrezia’s niece. Not the best match, but at least she was compatible.” _Not like the others. Not like my sister._ “But some of the Geisters didn’t want their goddess back. They taught her how to resist it. And when she saw…” _Anevka_. Zola had known his sister Before, recognized that what was left in the clank body was only a pale copy, but watching her shut Anevka down had brought back all the memories of the first time - the madness of guilt and despair and breakthrough, followed by the long slow realization that what remained was as much Lucrezia as it had been his sister. “She saw the perfect chance to have the one person at her back she could trust absolutely.”

Jenka pressed a claw under his chin to tip his head up so he’d have no choice but to meet her eyes. “Und vhat vas _hyur_ part in dis, _Valois?_ ” She made his family name sound like an insult.

“Puppet,” he said, staring back at her calmly. “Which is why I made my _own_ deal with the Castle.” At least he’d thought he had. He should have remembered the Castle’s notorious sense of humor.

_”Yes,”_ Tony - _the_ Heterodyne, Sparky harmonics in full force - said, sailing down from the ceiling. “He’s going to fix my Castle, so do try not to poke any unnecessary holes in him.”

~.~

Darcy looked idly at the holodisplay of Mechanicsburg. _If I were a portal, where would I be?_ There wasn’t much else she could do to help; everyone else had been busy since they’d gotten Tony’s report. Bruce and Jane were trying to figure out how to calibrate her devices now that they knew what kind of interference they were dealing with, with Thor alternating between offering advice and reciting snatches of ancient Asgardian sagas as he tried to determine just how whatever-it-was had gotten there. Clint had found a lookout position in the thick crossbeams of the lodge’s high pointed ceiling, where he could watch both the Sparks and the mountainside leading down to the town.

Higgs showed up with coffee, which Darcy took gratefully - even with the time zone change working in their favor, pre-dawn was a terrible time to be awake.

“Anything interesting?” he asked.

“Nothing so far. Just - ew, spiders!” She brushed at the scurrying figures, which… didn’t move. “Uh, oh.” She zoomed in on the town, and the spiders zoomed with it. “Um, guys? Unless that fancy church there is secretly a TARDIS, I think I found your portal.”

_That_ got everyone’s attention. Jane joined her at the table, poking and prodding at the holodisplay. “Can we get a look inside?”

Higgs shook his head. “We’ve never needed to. Everything’s been empty for decades.”

“OK, fine,” Jane said distractedly, as she pulled up a wireframe of the building and started manipulating it. Darcy tuned her out when she started muttering about angles and containment.

Clint called out, “That’s not the only problem. Something’s moving out there.”

Higgs did something to one of the displays and then frowned. “The motion detectors have been disabled -” He was cut off by an explosion that shook the building.

“That was the quinjet,” Clint said, dropping down from the ceiling. 

Jane looked up at him, irate. “They blew up our plane? They can’t do that, I need it to get down there!”

Darcy shared a long-suffering look with Higgs, who said “We’ve got another quinjet in the hangar. That won’t be as easy for them to take out - it’s one of the original buildings.”

“Bet they’ll be waiting for us,” Clint said. “It’s what I’d do.”

Thor hefted Mew-mew and smiled in grim anticipation. “Let them. I shall clear the way.” 

Higgs watched them gather Jane’s gear, then turned to Darcy. “We should be safe here once I’ve reset the defenses.”

Darcy’s eyes went to Bruce, who took a deep breath and gave her a tight smile that wasn’t as reassuring as he probably thought it was. _Not so much, then_. Normally part of her job as Spark wrangler - not minion, no matter what Higgs said - was to divert anything that might interfere with their work, which she’d taken to include anything that could stress Bruce out. Too bad Higgs had only shown her all the ways to get _back_ to the lodge…

“Hey. You know this place pretty well,” she said. “Any secret passages out of here? ‘Cause Bruce is looking a bit green.” He wasn’t, actually, but he did look grateful for the interference.

She could tell the moment Higgs worked out what would happen when _over-engineered Heterodyne defenses_ met _cornered Big Guy_. “Right. I think that’s a very good idea.”

~.~

Natasha and Tarvek traded a series of hand signals and then set off into the corridor, Tony behind them to provide as much covering fire as he could while still protecting the Castle’s clank body and the equipment they’d need to repair it. The four of them had made it nearly halfway to the library before encountering any of the Geisterdamen, but since then they’d been attacking with single-minded determination - Grandma Dearest had obviously told them where to go, because from outward appearances this corridor was a dead end. Steve and the Jägers were still down in the caverns, trying to hold off the rest of their army until Tony could get the Castle back online.

It didn’t take long to clear the corridor, what with the Wonder Twins moving together like they’d been doing it for years. The Castle led the way to one particular ornamental decoration. “Another gargoyle?” he grumbled, stripping off one of the gauntlets. “OK, biometrics, awesome - I mean, you shouldn’t even _have_ tech at that level - but does it have to _bite?_ ”

“You’re lucky. These are just the _small_ ones,” the Castle said smugly as the bricks slid aside.

He followed it through and stopped, staring up at a large room packed with books and devices, the shelves extending up farther than the light could reach. “How is this still _here?_ And I don’t care what Fury says, I am _keeping_ this library.” If they were anything like his father’s journals, they’d be mostly theory, underlaid with the frustration of having ideas that simply couldn’t be implemented - they’d had an Asgardian power supply and nothing close to the tech needed to take full advantage of it. But Tony _did_ …

“We never found it,” Tarvek said reverently. “It must have been sealed up since the first attack.”

Tony felt a flash of inexplicable annoyance - that had all happened long before he’d been born, so why did he feel so possessive? Natasha looked over at him as if she wasn’t sure whether guarding the door or watching him was a higher priority. _This place is starting to get to me._ “Right,” he said, shaking it off. “We’re here, now what?”

The Castle-clank pulled away a dusty rug to reveal a huge gem-studded device and - “A holodisplay? Seriously?” The lines were faint, but the shape of the Castle structure was unmistakable. Not a wireframe outline, though, more like - “Neural network?” 

“That, and more,” the Castle said, “but I’m so damaged - how did I even function?”

“You didn’t,” Tarvek said dryly. “By our estimates there may have been a dozen separate fragments, all working at cross-purposes. It made trying to negotiate _extremely_ difficult.”

“So where’s the access point?” If he was reading it right, one of the major neural clusters went through the room they were in. Behind the walls, maybe? This was a library; if there weren’t hidden rooms behind trick bookshelves he’d be very disappointed… yes, _there_.

“Classic,” Tony said, stepping out of the suit so he could look inside without snagging any of the equipment. “But the tech - stone knives and bearskins, seriously.” He couldn’t remember the last time he’d done any work of this nature with wires and circuits he could actually _see_. “OK, kid, you’re up.”

It didn’t take Tarvek much time to get the two parts of the Castle connected - as he explained, it was the same equipment Lucrezia had used for the original transfer, so it only needed recalibrating. Tarvek was much more considerate of the Muse’s body than its occupant was, carefully arranging the wings to avoid damage.

“Ready?” Tony asked, and pulled the switch at Tarvek’s nod. The Muse body twitched once and then went still.

“Ohhh.” The voice reverberated from the walls, much deeper than it had from the clank body. “I’d forgotten just how much _space_ I had. And how much I can _do_ … Yesss. That little problem we had downstairs has been taken care of.”

“Cap?” Tony asked over the comms. “What’s your situation?”

_“Ah, the roof just came down on the enemy,”_ Steve replied, sounding stunned.

“You OK?”

_“Yeah. It was a very… precise collapse.”_

_Oh._ Self-modifying castle, right. “Got it. Soon as you can, get out to the town. There’s another army coming through, and Hawkeye and Thor could use your help.”

_”Acknowledged.”_

“Another army?” the Castle asked. “Where are they? Wait, where is the _town?_ And my weapons, my Torchmen? My Fun-Sized Mobile Agony and Death Dispensers? I should have more power than this!”

The _what?_ “You know, I wasn’t going to say anything, but seriously? You have _issues_. And your weapons would be obsolete anyway - I’ve probably designed more advanced systems than that in my _sleep_.” Was he imagining things, or was that a low hum of approval? “Look, what we need now is to contain the enemy - you can do that, right?”

There was a pause as the holodisplay cycled through different modes. “Many of my systems are unavailable,” the Castle finally said, apologetically. “The charging stations must have been offline all this time. But if you get them reconnected, I think… yes, I can have the defenses working in under a year!”

“OK, you and I are going to have to have a talk about the wonders of modern self-sustaining clean energy systems…” Tony said, trying to make sense of the display. Some sections were red, some yellow - he thought he could make out a few self-contained pockets, but he had no clue if their isolation was intentional or not. Given enough time, maybe…

Tarvek joined him, looking thoughtful. “This would’ve been so useful when we were studying the Castle.”

“Stealing it, you mean,” Tony said. ”But hey, if you know more about the place than I do…” From the wary looks both Natasha and Tarvek gave him, that must have come out a bit more biting than he’d intended.

“That _wasn’t my plan,_ ” Tarvek grumbled. “And up to the end we _were_ trying to repair it. I studied all the reports I could get my hands on, but nothing compared to actually being here - even damaged, this is the most amazing construct I’ve ever seen.”

“Flatterer,” the Castle said. “I knew I kept you around for a reason.”

Tarvek looked unsettled at that, but covered it quickly. He walked around the display. “If this is your power system, then the lightning rods on the towers should be connected to it. We suspected as much but we could never get any repair crews up there.”

“Lightning rods, huh?” Tony said, summoning the suit. “If I can’t repair a simple electrical system, Cap’ll never let me hear the end of it.”

Tarvek frowned. “We still won’t have enough power.”

“No problem,” Tony said. He launched himself in the air and hovered a few feet above the ground while he considered how to best to make his exit. A shower of dust drifted down as the Castle obligingly opened a hole in the skylight. “You may be the Storm King, kid, but I have a lightning god on speed-dial.”

~.~

Lightning flashed over the city, illuminating an army of spiders closing in on their position. Jenka laid a hand on the ruined walls of the alley, hoping that this time the city would have awoken. No luck. They’d rendezvoused with the quinjet to pick up Dr Foster’s devices, and had managed to plant three of them before attracting the Geister’s attention. Two more - at least - to go, to seal off the portal and the rest of their army.

“Hawkeye, Hy need zome optionz here,” she said.

“Looks like they’re closing in on you from all sides. Iron Man?”

“Busy here.” Tony’s voice sounded like he was deep in the Madness Place. “Even once I get it charged I’ve still got to figure out what it’s even supposed to do, and then…” She tuned him out from long experience.

Jenka traded a grim look with the others. Three against an army wasn’t the worst odds she and Maxim had ever faced, and Steve didn’t seem that resigned either. “Maybe we can sneak-“ he started, when Darcy’s voice cut in on the comms.

“Hey, guys, if you can hold on just a bit, Fezzik and the Brute Squad should be just about there.”

Steve and Maxim traded puzzled looks. Jenka nudged them and pointed at the Geister swarm - something behind them had drawn their attention. Lightning crashed again, illuminating a colorful blur of - 

“Jägers?”

Geisterdamen and spiders flew through the air, harder and faster than Jenka had ever seen anyone other than a general manage. Within moments a path was cleared. Jenka looked up - and up. “Hulk?” 

He paused and grinned. “Pretty fighting lady!”

She smiled in return and leapt into the melee, Maxim and Steve at her back. “Yah. Ve _fight!_ ”

**Author's Note:**

> The mad science is closer to the Avengers' level than Girl Genius, which still leaves a lot of room for constructs, clanks, and portals to alien dimensions, but not mass destruction of England and Norway. The Great Spark War occured near the end of the 19th century and ended with the mutal destruction of Castles Wulfenbach and Heterodyne, followed by the collapse of the Wulfenbach Empire.


End file.
